func_code_string: #include <bits/stdc++.h>   using namespace std;   vector<int> g[100005];   double dfs(int i, int ult) {     double ans = 0;     int c = g[i].size() - (i != 1);     for (int j = 0; j < g[i].size(); j++) {       if (g[i][j] != ult) {         ans += (dfs(g[i][j], i) + 1.0) / c;       }     }     return ans;   }   int main() {     int n;     scanf( %d , &n);     for (int i = 1; i < n; i++) {       int a, b;       scanf( %d %d , &a, &b);       g[a].push_back(b);       g[b].push_back(a);     }     printf( %.15lf n , dfs(1, 0));   }   