func_code_string: #include <bits/stdc++.h>   using namespace std;   int a[100005], ans[100005];   int main() {     int n, a1, a2, num = 0, gg = 0, t = 0;     cin >> n;     bool ty = true, zz = true;     for (int i = 1; i <= n - 1; ++i) {       cin >> a1 >> a2;       a[a1]++;       a[a2]++;     }     for (int i = 1; i <= n; ++i) {       if (a[i] > 2) {         num++;         gg = i;       }       if (num > 1) {         ty = false;         break;       } else if (a[i] == 1) {         ans[i] = i;         t++;       }     }     if (!ty) {       cout <<  No  << endl;     } else {       cout <<  Yes  << endl;       if (num == 1) {         cout << t << endl;         for (int i = 1; i <= n; ++i) {           if (ans[i] != 0) {             cout << gg <<     << ans[i] << endl;           }         }       } else {         cout << 1 << endl;         for (int i = 1; i <= n; ++i) {           if (ans[i] != 0 && zz) {             cout << ans[i] <<    ;             zz = false;           } else if (ans[i] != 0 && !zz) {             cout << ans[i] << endl;           }         }       }     }     return 0;   }   