func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n, m;     cin >> n >> m;     unordered_map<int, int> mp;     vector<int> v[n + 1];     for (int i = 0; i < m; i++) {       int x, y;       cin >> x >> y;       v[x].push_back(y);       v[y].push_back(x);     }     vector<int> t;     int ans = 0;     while (1) {       int num = 0;       vector<int> t;       for (int i = 1; i <= n; i++) {         if (v[i].size() == 1) {           num++;           t.push_back(i);         }       }       if (num > 0) {         ans++;         for (int i = 0; i < num; i++) {           int neigh = v[t[i]][0];           v[t[i]].clear();           v[neigh].erase(remove(v[neigh].begin(), v[neigh].end(), t[i]),                          v[neigh].end());         }       } else {         break;       }     }     cout << ans << endl;   }   