diff --git a/.gitignore b/.gitignore
index 2d1b1b4..ec5cd35 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,3 @@
 *.o
-*.d
+*.d*
 output.txt
diff --git a/.vscode/launch.json b/.vscode/launch.json
index e958803..00fb2c5 100644
--- a/.vscode/launch.json
+++ b/.vscode/launch.json
@@ -9,7 +9,7 @@
             "type": "cppdbg",
             "request": "launch",
             "program": "${workspaceFolder}/atpg",
-            "args": ["c432.bench"],
+            "args": ["test.bench"],
             "stopAtEntry": false,
             "cwd": "${fileDirname}",
             "environment": [],
diff --git a/CNC-LS b/CNC-LS
new file mode 160000
index 0000000..d912260
--- /dev/null
+++ b/CNC-LS
@@ -0,0 +1 @@
+Subproject commit d9122607522ea757b3412f1cff247b9db6c79c55
diff --git a/atpg b/atpg
index 962262b..23634ff 100755
Binary files a/atpg and b/atpg differ
diff --git a/circuit.cpp b/circuit.cpp
index 7e5b315..a2b037f 100644
--- a/circuit.cpp
+++ b/circuit.cpp
@@ -4,6 +4,7 @@
 #include <unordered_map>
 #include <unordered_set>
 #include "assert.h"
+#include "clause.h"
 
 void Circuit::init_topo_index() {
 
@@ -28,6 +29,10 @@ void Circuit::init_topo_index() {
         }
     }
 
+    for(Gate* g : gates) {
+        id2gate[g->id] = g;
+    }
+
     // 计算反向拓扑序
     topo = 1;
     std::unordered_map<Gate*, int> outs;
diff --git a/circuit.h b/circuit.h
index f1bdf1d..b7a0f9c 100644
--- a/circuit.h
+++ b/circuit.h
@@ -61,7 +61,7 @@ std::vector<Gate*> POs;
 std::vector<Gate*> gates;
 std::vector<Gate*> rtopo_gates;
 std::vector<Gate*> stems; // PIs and POs are stems by default
-
+std::unordered_map<int, Gate*> id2gate;
 std::unordered_map<std::string, Gate*> name2gate;
 
 // 读入和输出电路
@@ -100,12 +100,13 @@ void ls_statistics();
 
 void ls_update_weight();
 
-Gate* ls_pick();
+int ls_pick();
 Gate* ls_pick_falsified();
 
-void ls_flip(Gate* stem);
+void ls_flip_var(int var);
+void ls_flip_stem(Gate* stem);
 
-ll ls_pick_score(Gate* stem);
+ll ls_pick_score(int var);
 
 ll ls_circuit_score();
 
diff --git a/clause.cpp b/clause.cpp
new file mode 100644
index 0000000..3bb85d9
--- /dev/null
+++ b/clause.cpp
@@ -0,0 +1,275 @@
+#include "clause.h"
+
+ll Clause::total_cost;
+
+void Clause::update_satisfied_lit_count() {
+
+    using namespace ClauseLS;
+
+    ll old_lit_count = satisfied_lit_count;
+
+    satisfied_lit_count = 0;
+
+    for(auto& lit : lits) {
+        if(lit_value[abs(lit)]) {
+            satisfied_lit_count += (lit > 0);
+        } else {
+            satisfied_lit_count += (lit < 0);
+        }
+    }
+
+    if(old_lit_count == 0 && satisfied_lit_count > 0) {
+        falsified_clauses.erase(this);
+        total_cost -= weight;
+        satisfied_clauses.insert(this);
+    }
+
+    if(old_lit_count > 0 && satisfied_lit_count == 0) {
+        satisfied_clauses.erase(this);
+        total_cost += weight;
+        falsified_clauses.insert(this);
+    }
+}
+
+namespace ClauseLS {
+
+int num_vars;
+int num_clauses;
+
+std::unordered_set<Clause*> satisfied_clauses;
+std::unordered_set<Clause*> falsified_clauses;
+
+std::vector<Clause*> clauses;
+std::vector<Clause*> *lit_related_clauses;
+int *lit_value;
+int *CC;
+
+void flip(int var) {
+
+    // printf("value: [ ");
+
+    // for(int i=1; i<=num_vars; i++) {
+    //     printf("%d ", lit_value[i]);
+    // }
+
+    // printf("]\n");
+
+    // for(auto& c : clauses) {
+        
+    //     printf("lits: [ ");
+    //     for(auto& lit : c->lits) {
+    //         printf("%d ", lit);
+    //     }
+    //     printf(" ] satifs_cnt: %d\n", c->satisfied_lit_count);
+
+    // }
+
+    lit_value[var] = !lit_value[var];
+
+    for(auto& clause : lit_related_clauses[var]) {
+        clause->update_satisfied_lit_count();
+        for(auto& lit : clause->lits) {
+            CC[abs(lit)] = 1;
+        }
+    }
+    CC[var] = 0;
+
+
+
+}
+
+void add_to_tmp_clause(int x) {
+    static std::vector<int> lits;
+    if(x != 0) {
+        lits.push_back(x);
+    } else {
+        Clause* clause = new Clause();
+        clause->lits = lits;
+        clause->satisfied_lit_count = 0;
+        clauses.push_back(clause);
+        lits.clear();
+    }
+}
+
+void init_data_structs(Circuit* circuit) {
+    build_clauses(circuit);
+
+    printf("====== Clause Statistics ====== \n");
+    printf("num_vars:\t%d\n", num_vars);
+    printf("num_clauses:\t%ld\n", num_clauses);
+    printf("================================ \n");
+
+    lit_related_clauses = new std::vector<Clause*>[num_vars + 1];
+    lit_value = new int[num_vars + 1];
+    CC = new int[num_vars + 1];
+
+    for(int i=1; i<=num_vars; i++) {
+        lit_value[i] = 0;
+        CC[i] = 1;
+    }
+
+    for(auto& clause : clauses) {
+        clause->weight = 1;
+        Clause::total_cost += clause->weight;
+        falsified_clauses.insert(clause);
+
+        //printf("fs: %d. ss: %d\n", falsified_clauses.size(), satisfied_clauses.size());
+        
+        clause->update_satisfied_lit_count();
+
+        for(auto& lit : clause->lits) {
+            lit_related_clauses[abs(lit)].push_back(clause);
+        }
+    }
+}
+
+void reset_data_structs() {
+    for(int i=1; i<=num_vars; i++) {
+        lit_value[i] = 0;
+    }
+}
+
+void build_clauses(Circuit* circuit) {
+
+    int extra_variable = circuit->gates.size();
+
+    int last_id, last_v;
+
+    for(Gate* g : circuit->gates) {
+        if(g->pi) continue;
+
+        switch(g->type) {
+            case Gate::NOT:
+                add_to_tmp_clause(-g->id);
+                add_to_tmp_clause(-(g->fan_ins[0]->id));
+                add_to_tmp_clause(0);
+
+                add_to_tmp_clause(g->id);
+                add_to_tmp_clause(-(g->fan_ins[0]->id));
+                add_to_tmp_clause(0);
+                break;
+            case Gate::BUF:
+                add_to_tmp_clause(-g->id);
+                add_to_tmp_clause((g->fan_ins[0]->id));
+                add_to_tmp_clause(0);
+
+                add_to_tmp_clause(g->id);
+                add_to_tmp_clause(-(g->fan_ins[0]->id));
+                add_to_tmp_clause(0);
+                break;
+            case Gate::AND:
+                for(int i=1; i<g->fan_ins.size(); i++) {
+                    add_to_tmp_clause(-g->id);
+                    add_to_tmp_clause(g->fan_ins[i]->id);
+                    add_to_tmp_clause(0);
+                }
+
+                for(int i=1; i<g->fan_ins.size(); i++) {
+                    add_to_tmp_clause(-g->fan_ins[i]->id);
+                }
+                add_to_tmp_clause(g->id);
+                add_to_tmp_clause(0);
+                break;
+            case Gate::NAND:
+                for(int i=1; i<g->fan_ins.size(); i++) {
+                    add_to_tmp_clause(g->id);
+                    add_to_tmp_clause(g->fan_ins[i]->id);
+                    add_to_tmp_clause(0);
+                }
+
+                for(int i=1; i<g->fan_ins.size(); i++) {
+                    add_to_tmp_clause(-g->fan_ins[i]->id);
+                }
+                add_to_tmp_clause(-g->id);
+                add_to_tmp_clause(0);
+                break;
+            case Gate::OR:
+                for(int i=1; i<g->fan_ins.size(); i++) {
+                    add_to_tmp_clause(g->fan_ins[i]->id);
+                }
+                add_to_tmp_clause(-g->id);
+                add_to_tmp_clause(0);
+
+                for(int i=1; i<g->fan_ins.size(); i++) {
+                    add_to_tmp_clause(g->id);
+                    add_to_tmp_clause(-g->fan_ins[i]->id);
+                    add_to_tmp_clause(0);
+                }
+                break;
+            case Gate::NOR:
+                for(int i=1; i<g->fan_ins.size(); i++) {
+                    add_to_tmp_clause(g->fan_ins[i]->id);
+                }
+                add_to_tmp_clause(g->id);
+                add_to_tmp_clause(0);
+
+                for(int i=1; i<g->fan_ins.size(); i++) {
+                    add_to_tmp_clause(-g->id);
+                    add_to_tmp_clause(-g->fan_ins[i]->id);
+                    add_to_tmp_clause(0);
+                }
+                break;
+            case Gate::XOR:
+                last_v = g->fan_ins[0]->id;
+                for(int i=1; i<g->fan_ins.size() - 1; i++) {
+                    int new_v = ++extra_variable;
+                    add_to_tmp_clause(-g->fan_ins[i]->id); add_to_tmp_clause(-last_v); add_to_tmp_clause(-new_v);
+                    add_to_tmp_clause(0);
+                    add_to_tmp_clause(-g->fan_ins[i]->id); add_to_tmp_clause(last_v); add_to_tmp_clause(new_v);
+                    add_to_tmp_clause(0);
+                    add_to_tmp_clause(g->fan_ins[i]->id); add_to_tmp_clause(-last_v); add_to_tmp_clause(new_v);
+                    add_to_tmp_clause(0);
+                    add_to_tmp_clause(g->fan_ins[i]->id); add_to_tmp_clause(last_v); add_to_tmp_clause(-new_v);
+                    add_to_tmp_clause(0);
+                    last_v = new_v;
+                }
+
+                last_id = g->fan_ins[g->fan_ins.size() - 1]->id;
+
+                add_to_tmp_clause(-g->id); add_to_tmp_clause(-last_v); add_to_tmp_clause(-last_id);
+                add_to_tmp_clause(0);
+                add_to_tmp_clause(-g->id); add_to_tmp_clause(last_v); add_to_tmp_clause(last_id);
+                add_to_tmp_clause(0);
+                add_to_tmp_clause(g->id); add_to_tmp_clause(-last_v); add_to_tmp_clause(last_id);
+                add_to_tmp_clause(0);
+                add_to_tmp_clause(g->id); add_to_tmp_clause(last_v); add_to_tmp_clause(-last_id);
+                add_to_tmp_clause(0);
+
+                break;
+            case Gate::XNOR:
+                last_v = g->fan_ins[0]->id;
+                for(int i=1; i<g->fan_ins.size() - 1; i++) {
+                    int new_v = ++extra_variable;
+                    add_to_tmp_clause(-g->fan_ins[i]->id); add_to_tmp_clause(-last_v); add_to_tmp_clause(-new_v);
+                    add_to_tmp_clause(0);
+                    add_to_tmp_clause(-g->fan_ins[i]->id); add_to_tmp_clause(last_v); add_to_tmp_clause(new_v);
+                    add_to_tmp_clause(0);
+                    add_to_tmp_clause(g->fan_ins[i]->id); add_to_tmp_clause(-last_v); add_to_tmp_clause(new_v);
+                    add_to_tmp_clause(0);
+                    add_to_tmp_clause(g->fan_ins[i]->id); add_to_tmp_clause(last_v); add_to_tmp_clause(-new_v);
+                    add_to_tmp_clause(0);
+                    last_v = new_v;
+                }
+
+                last_id = g->fan_ins[g->fan_ins.size() - 1]->id;
+
+                add_to_tmp_clause(g->id); add_to_tmp_clause(-last_v); add_to_tmp_clause(-last_id);
+                add_to_tmp_clause(0);
+                add_to_tmp_clause(g->id); add_to_tmp_clause(last_v); add_to_tmp_clause(last_id);
+                add_to_tmp_clause(0);
+                add_to_tmp_clause(-g->id); add_to_tmp_clause(-last_v); add_to_tmp_clause(last_id);
+                add_to_tmp_clause(0);
+                add_to_tmp_clause(-g->id); add_to_tmp_clause(last_v); add_to_tmp_clause(-last_id);
+                add_to_tmp_clause(0);
+                break;
+            default:
+                exit(-1);
+                break;
+        }
+    }
+
+    num_vars = extra_variable;
+    num_clauses = clauses.size();
+}
+
+}
\ No newline at end of file
diff --git a/clause.h b/clause.h
new file mode 100644
index 0000000..b09aca6
--- /dev/null
+++ b/clause.h
@@ -0,0 +1,36 @@
+#pragma once
+
+#include <vector>
+#include <unordered_map>
+#include <unordered_set>
+
+#include "circuit.h"
+
+class Clause {
+public:
+int satisfied_lit_count;
+int weight;
+static ll total_cost;
+std::vector<int> lits;
+void update_satisfied_lit_count();
+};
+
+namespace ClauseLS {
+
+    extern int num_vars;
+    extern int num_clauses;
+
+    extern std::vector<Clause*> clauses;
+    extern std::vector<Clause*> *lit_related_clauses;
+    extern int *lit_value;
+    extern int *CC;
+    extern std::unordered_set<Clause*> satisfied_clauses;
+    extern std::unordered_set<Clause*> falsified_clauses;
+
+    void init_data_structs(Circuit* circuit);
+    void reset_data_structs();
+    void add_to_tmp_clause(int x);
+    void build_clauses(Circuit* circuit);
+
+    void flip(int var);
+}
\ No newline at end of file
diff --git a/gate_encode.txt b/gate_encode.txt
new file mode 100644
index 0000000..c82eedc
--- /dev/null
+++ b/gate_encode.txt
@@ -0,0 +1,10 @@
+
+NOT:
+1.
+a <=> ~b
+2.
+a => ~b
+~b => a
+3.
+
+
diff --git a/ls.cpp b/ls.cpp
index 67e4fe0..2d03e4d 100644
--- a/ls.cpp
+++ b/ls.cpp
@@ -7,6 +7,8 @@
 #include "assert.h"
 #include <chrono>
 
+#include "clause.h"
+
 bool Circuit::local_search() {
 
     ls_reset_data();
@@ -20,25 +22,21 @@ bool Circuit::local_search() {
     for(int i=0; i<MAX_STEPS; i++) {
 
         auto start = std::chrono::system_clock::now();
+        printf("[FLIP] stem: %lld, fault:%lld, stem_cnt: %lld, fault_cnt:%lld, fpl_score: %lld citcuit-score: %lld\n", stem_total_cost, fault_total_weight, stem_total_cnt, fault_total_cnt, fault_propagate_score, ls_circuit_score());
 
-        //printf("[FLIP] stem: %lld, fault:%lld, stem_cnt: %lld, fault_cnt:%lld, fpl_score: %lld citcuit-score: %lld\n", stem_total_cost, fault_total_weight, stem_total_cnt, fault_total_cnt, fault_propagate_score, ls_circuit_score());
+        int id = ls_pick();
 
-        Gate* stem = ls_pick();
+        printf("pick: %d\n", id);
 
-        if(stem == nullptr) {
-            //printf("[UP] stem: %lld, fault:%lld, stem_cnt: %lld, fault_cnt:%lld, fpl_score: %lld citcuit-score: %lld\n", stem_total_cost, fault_total_weight, stem_total_cnt, fault_total_cnt, fault_propagate_score, ls_circuit_score());
-            ls_update_weight();
-
-            stem = ls_pick_falsified();
-        }
+        //printf("flip: %d.  fc: %d.  %d\n", id, ClauseLS::falsified_clauses.size(), Clause::total_cost);
 
         if(stem_total_cnt == stems.size()) {
             //printf("FIND SOLUTION!\n");
-            //printf("[SOL] flip: %lld, stem: %lld, fault:%lld. flip_cnt: %d, stem_cnt: %d, fault_cnt:%d\n", flip_total_weight, stem_total_weight, fault_total_weight, flip_total_cnt, stem_total_cnt, fault_total_cnt);
+            printf("[UP] stem: %lld, fault:%lld, stem_cnt: %lld, fault_cnt:%lld, fpl_score: %lld citcuit-score: %lld\n", stem_total_cost, fault_total_weight, stem_total_cnt, fault_total_cnt, fault_propagate_score, ls_circuit_score());
             break;
         }
 
-        ls_flip(stem);
+        ls_flip_var(id);
 
         assert(is_valid_circuit());
 
@@ -82,11 +80,12 @@ void Circuit::ls_statistics() {
 void Circuit::ls_update_weight() {
 
     if(rand() % 10000 <= SP * 10000) {
-        for(Gate* g : gates) {
-            if(g->stem && g->stem_satisfied && (g->stem_weight - STEM_INC >= 1)) {
-                g->stem_weight -= STEM_INC;
-            }
+        for(auto& clause : ClauseLS::satisfied_clauses) {
+            if(clause->weight - CLAUSE_FALSIFIED_INC < 1) continue;
+            clause->weight -= CLAUSE_FALSIFIED_INC;
+        }
 
+        for(Gate* g : gates) {
             if(g->fault_detected[0] && g->fault_weight[0] - FAULT_INC >= 1) {
                 g->fault_weight[0] -= FAULT_INC;
                 fault_propagate_score -= FAULT_INC * (g->fault_propagate_length[0]);
@@ -98,21 +97,13 @@ void Circuit::ls_update_weight() {
             }
         }
     } else {
+        for(auto& clause : ClauseLS::falsified_clauses) {
+            if(clause->weight + CLAUSE_FALSIFIED_INC > CLAUSE_FALSIFIED_MAX) continue;
+            clause->weight += CLAUSE_FALSIFIED_INC;
+            clause->total_cost += CLAUSE_FALSIFIED_INC;
+        }
+
         for(Gate* g : gates) {
-            if(g->stem && !g->stem_satisfied && (g->stem_weight + STEM_INC < STEM_WEIGHT_MAX)) {
-                g->stem_weight += STEM_INC;
-                stem_total_cost += STEM_INC;
-
-                for(Gate* suc : g->suc_stems) {
-                    if(suc->stem_weight - STEM_INC >= 1) {
-                        suc->stem_weight -= STEM_INC;
-                        if(!suc->stem_satisfied) {
-                            stem_total_cost -= STEM_INC;
-                        }
-                    }
-                }
-            }
-
             if(!g->fault_detected[0] && g->fault_weight[0] > 0 && (g->fault_weight[0] + FAULT_INC < FAULT_WEIGHT_MAX)) {
                 g->fault_weight[0] += FAULT_INC;
                 fault_propagate_score += FAULT_INC * (g->fault_propagate_length[0]);
@@ -126,57 +117,39 @@ void Circuit::ls_update_weight() {
     }
 }
 
-Gate* Circuit::ls_pick() {
-    Gate* stem = nullptr;
+int Circuit::ls_pick() {
+    int var = -1;
     ll max_score = 0;
-        
-    std::vector<Gate*> stems_random;
-    std::vector<Gate*> candidates;
 
-    for(int i=0; i<stems.size(); i++) {
-        if(stems[i]->CC) {
-            stems_random.push_back(stems[i]);
-        }
-    }
+    for(int i=0; i<SAMPLING_COUNT; i++) {
+        int t_var = rand() % ClauseLS::num_vars + 1;
+        if(!ClauseLS::CC[t_var]) continue;
 
-    for(int i=0; i<stems_random.size(); i++) {
-        std::swap(stems_random[i], stems_random[rand()%stems_random.size()]);
-    }
-
-    const int max_index = std::min((int)stems_random.size(), SAMPLING_COUNT);
-
-    for(int i=0; i<max_index; i++) {
-        Gate* t_stem = stems_random[i];
-        ll t_score = ls_pick_score(t_stem);
+        ll t_score = ls_pick_score(t_var);
         
         if(t_score > max_score) {
             max_score = t_score;
-            stem = t_stem;
+            var = t_var;
         }
     }
 
-    return stem;
-}
+    if(var == -1) {
+        ls_update_weight();
 
-Gate* Circuit::ls_pick_falsified() {
-    std::vector<Gate*> candidates;
-    for(Gate *g : stems) {
-        if(g->stem_satisfied) continue;
+        printf("[UP]\n");
 
-        // for(Gate* pre : g->pre_stems)
-        //     candidates.push_back(pre);
+        printf("fals: %d\n", ClauseLS::falsified_clauses.size());
 
-        // for(Gate* suc : g->suc_stems)
-        //     candidates.push_back(suc);
+        auto it = std::next(ClauseLS::falsified_clauses.begin(), rand() % ClauseLS::falsified_clauses.size());
 
-        candidates.push_back(g);
+        auto& lits = (*it)->lits;
+
+        var = abs(lits[rand()%lits.size()]);
     }
 
-    if(candidates.size() == 0) {
-        candidates.push_back(stems[rand()%stems.size()]);
-    }
+    assert(var != -1);
 
-    return candidates[rand()%candidates.size()];
+    return var;
 }
 
 void Circuit::ls_init_stems() {
@@ -241,15 +214,27 @@ void Circuit::ls_init_stems() {
     }
 }
 
-ll Circuit::ls_pick_score(Gate* stem) {
+void Circuit::ls_flip_var(int var) {
+
+
+    
+
+    ClauseLS::flip(var);
+
+    if(id2gate.count(var) && id2gate[var]->stem) {
+        ls_flip_stem(id2gate[var]);
+    }
+}
+
+ll Circuit::ls_pick_score(int var) {
 
     ll old_score = ls_circuit_score();
 
-    ls_flip(stem);
+    ls_flip_var(var);
 
     ll new_score = ls_circuit_score();
 
-    ls_flip(stem);
+    ls_flip_var(var);
 
     assert(old_score == ls_circuit_score());
 
@@ -257,7 +242,8 @@ ll Circuit::ls_pick_score(Gate* stem) {
 }
 
 ll Circuit::ls_circuit_score() {
-    ll score = -stem_total_cost + fault_propagate_score + fault_total_weight;
+    //ll score = - Clause::total_cost + fault_propagate_score + fault_total_weight;
+    ll score = - Clause::total_cost;
     return score;
 }
 
@@ -277,7 +263,7 @@ void Circuit::ls_random_circuit() {
 
     // init assignment
     for(Gate* s : stems) {
-        s->value = rand() % 2;
+        s->value = ClauseLS::lit_value[s->id];
     }
 
     // recal value by topo
@@ -345,7 +331,7 @@ void Circuit::ls_reset_data() {
 }
 
 
-void Circuit::ls_flip(Gate* stem) {
+void Circuit::ls_flip_stem(Gate* stem) {
     stem->value = !stem->value;
 
     // update CC
diff --git a/main.cpp b/main.cpp
index 98258e3..9cc0d36 100644
--- a/main.cpp
+++ b/main.cpp
@@ -3,6 +3,7 @@
 #include <assert.h>
 
 #include "circuit.h"
+#include "clause.h"
 
 int main(int args, char* argv[]) {
 
@@ -29,6 +30,9 @@ int main(int args, char* argv[]) {
 
     circuit->global_fault_undetected_count = circuit->gates.size() * 2;
 
+    // init clause local search
+    ClauseLS::init_data_structs(circuit);
+
     while(true) {
         bool ls = circuit->local_search();
         bool is_valid = circuit->is_valid_circuit();
diff --git a/option.h b/option.h
index 222a1ad..8c0566f 100644
--- a/option.h
+++ b/option.h
@@ -1,9 +1,9 @@
 #pragma once
 
 const double SP = 0.01;
-const int MAX_STEPS = 10000;
+const int MAX_STEPS = 1000000000;
 
-const int SAMPLING_COUNT = 25;
+const int SAMPLING_COUNT = 1000;
 
 const int STEM_INC = 2;
 const int STEM_WEIGHT_MAX = 1e9;
@@ -11,3 +11,5 @@ const int STEM_WEIGHT_MAX = 1e9;
 const int FAULT_INC = 1;
 const int FAULT_WEIGHT_MAX = 20;
 
+const int CLAUSE_FALSIFIED_INC = 2;
+const int CLAUSE_FALSIFIED_MAX = 1e9;
\ No newline at end of file
diff --git a/test.bench b/test.bench
new file mode 100644
index 0000000..0e976e8
--- /dev/null
+++ b/test.bench
@@ -0,0 +1,10 @@
+
+
+INPUT(1)
+INPUT(2)
+INPUT(3)
+
+OUTPUT(5)
+
+4 = XOR(1, 2)
+5 = XOR(3, 4)
\ No newline at end of file