func_code_string: #include <bits/stdc++.h>   using namespace std;   using li = long long;   using ld = long double;   using pii = pair<int, int>;   const int INF = 1e9 + 13;   const int N = 2e5 + 13;   const int M = 1e9 + 7;   const int B = 600;   const int A = 256;   const ld e = 1e-8;   const int LOGN = 20;   mt19937 rnd(time(0));   void solve() {     int n, m;     cin >> n >> m;     vector<bool> a(n, false);     for (int i = 0; i < m; i++) {       int x, y, z;       cin >> x >> y >> z;       y--;       a[y] = true;     }     int v = -1;     for (int i = 0; i < n; i++)       if (!a[i]) v = i;     for (int i = 0; i < n; i++) {       if (i != v) cout << v + 1 <<     << i + 1 <<   n ;     }   }   int main() {     ios::sync_with_stdio(0);     cin.tie(0);     int t = 1;     cin >> t;     while (t--) solve();   }   