func_code_string: #include <bits/stdc++.h>   #pragma GCC optimize( O3 )   using namespace std;   using ll = long long;   using ii = pair<int, int>;   using uint = unsigned int;   const int N = 1e5 + 5, MOD = 1e9 + 7;   int main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     int n;     cin >> n;     vector<int> deg(n + 1);     for (int i = 1, u, v; i < n; i++) {       cin >> u >> v;       deg[u]++;       deg[v]++;     }     if (find(deg.begin(), deg.end(), 2) == deg.end())       cout <<  YES n ;     else       cout <<  NO n ;     return 0;   }   