func_code_string: #include <bits/stdc++.h>   using namespace std;   vector<int> g[4111];   int f[4111], v[4111][4111];   int main() {     int n, m;     cin >> n >> m;     while (m--) {       int a, b;       cin >> a >> b;       if (a > b) swap(a, b);       g[a].push_back(b);       f[a]++;       f[b]++;       v[a][b] = v[b][a] = 1;     }     int ans = -1;     for (int i = 1; i <= n; i++) {       for (int j = 0; j < g[i].size(); j++) {         for (int k = j + 1; k < g[i].size(); k++) {           int a = g[i][j], b = g[i][k];           int w = f[a] + f[b] + f[i] - 6;           if (v[a][b]) {             if (ans == -1)               ans = w;             else               ans = min(ans, w);           }         }       }     }     cout << ans;   }   