func_code_string: #include <bits/stdc++.h>   using namespace std;   int ct[300005];   vector<pair<int, int> > val;   int n, m;   bool check(int vl) {     for (int i = 0; i < 300005; i++) ct[i] = 0;     int count = 0;     for (int i = 0; i < m; i++) {       if (vl != val[i].first && vl != val[i].second) {         count++;         ct[val[i].first]++;         if (val[i].second != val[i].first) {           ct[val[i].second]++;         }       }     }     if (count == 0) return true;     for (int i = 1; i < 300001; i++) {       if (ct[i] == count) {         return true;       }     }     return false;   }   int main() {     cin >> n >> m;     for (int i = 0; i < m; i++) {       int a, b;       cin >> a >> b;       val.push_back(make_pair(a, b));     }     int first = val[0].first;     int second = val[0].second;     if (check(first)) {       cout <<  YES n ;     } else if (check(second)) {       cout <<  YES n ;     } else {       cout <<  NO n ;     }   }   