func_code_string: #include <bits/stdc++.h>   using namespace std;   using ll = long long;   const ll inf = 1e18;   int n, m;   int edges[22][2];   bool used[6][6];   int arr[7];   void init() {}   void input() {     cin >> n >> m;     for (int i = 0; i < m; i++) {       cin >> edges[i][0] >> edges[i][1];       edges[i][0]--;       edges[i][1]--;     }   }   int check() {     int now = 0;     for (int i = 1; i <= 6; i++) {       for (int j = 1; j <= 6; j++) {         used[i][j] = false;       }     }     for (int i = 0; i < m; i++) {       int v = edges[i][0], u = edges[i][1];       if (!used[arr[v]][arr[u]]) {         now++;         used[arr[v]][arr[u]] = true;         used[arr[u]][arr[v]] = true;       }     }     return now;   }   void solve() {     int ans = 0;     for (arr[0] = 1; arr[0] < 7; arr[0]++) {       for (arr[1] = 1; arr[1] < 7; arr[1]++) {         for (arr[2] = 1; arr[2] < 7; arr[2]++) {           for (arr[3] = 1; arr[3] < 7; arr[3]++) {             for (arr[4] = 1; arr[4] < 7; arr[4]++) {               for (arr[5] = 1; arr[5] < 7; arr[5]++) {                 for (arr[6] = 1; arr[6] < 7; arr[6]++) {                   ans = max(ans, check());                 }               }             }           }         }       }     }     cout << ans << endl;   }   void output() {}   int main() {     ios::sync_with_stdio(false);     cin.tie(0);     int number_of_testcases = 1;     while (number_of_testcases--) {       init();       input();       solve();       output();     }     return 0;   }   