func_code_string: #include <bits/stdc++.h>   using namespace std;   #pragma GCC optimize( Ofast )   #pragma GCC target( sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma )   #pragma GCC optimize( unroll-loops )   const long long int mod = 1e9 + 7;   const long long int mod1 = 998244353;   const long long int inf = 1e18;   const long long int MX = 1e6 + 1;   const double PI = 3.141592653589793238;   template <typename T>   ostream& operator<<(ostream& out, const vector<T>& v) {     out <<  [ ;     for (auto i = v.begin(); i != v.end(); i++)       out << (i != v.begin() ?  ,  :   ) << (*i);     return (out <<  ] );   }   template <typename T>   ostream& operator<<(ostream& out, const set<T>& s) {     out <<  [ ;     for (auto i = s.begin(); i != s.end(); i++)       out << (i != s.begin() ?  ,  :   ) << (*i);     return (out <<  ] );   }   template <typename T>   ostream& operator<<(ostream& out, const unordered_set<T>& s) {     out <<   n  <<  [ ;     for (auto i = s.begin(); i != s.end(); i++)       out << (i != s.begin() ?  ,  :   ) << (*i);     return (out <<  ] );   }   template <typename T1, typename T2>   ostream& operator<<(ostream& out, const pair<T1, T2>& p) {     return (out <<  (  << p.first <<  ,  << p.second <<  ) );   }   template <typename T1, typename T2>   ostream& operator<<(ostream& out, const map<T1, T2>& m) {     out <<  {  <<   n ;     for (auto x : m) out <<      << x.first <<   ->   << x.second <<   n ;     return (out <<  } );   }   template <typename T1, typename T2>   ostream& operator<<(ostream& out, const unordered_map<T1, T2>& m) {     out <<  {  <<   n ;     for (auto x : m) out <<      << x.first <<   ->   << x.second <<   n ;     return (out <<  } );   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cout.tie(NULL);     long long int t;     cin >> t;     cin.ignore();     while (t--) {       long long int n, m;       cin >> n >> m;       map<long long int, long long int> mp;       for (long long int i = 0; i < m; i++) {         long long int x, y, z;         cin >> x >> y >> z;         mp[y]++;       }       long long int p1 = 0;       for (long long int i = 0; i < n; i++) {         if (mp.find(i + 1) == mp.end()) {           p1 = i + 1;           break;         }       }       for (long long int i = 0; i < n; i++) {         if (i + 1 == p1) {           continue;         }         cout << p1 <<     << i + 1 <<   n ;       }     }   }   