func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long INF = 1e17 + 9;   double ans = 0;   vector<int> adj[100009];   int vis[100009];   double dfs(int x, double prof) {     vis[x] = 1;     double ret = 1 / prof;     for (auto e : adj[x]) {       if (vis[e] == -1) ret += dfs(e, prof + 1);     }     return ret;   }   int main() {     ios::sync_with_stdio(false);     cin.tie(0);     memset(vis, -1, sizeof vis);     cout << fixed << setprecision(6);     long long n;     cin >> n;     long long m = n - 1;     while (m--) {       long long a, b;       cin >> a >> b;       adj[a].push_back(b);       adj[b].push_back(a);     }     cout << dfs(1, 1) <<   n ;     return 0;   }   