func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = (int)1e6 + 123;   const long long INF = (long long)1e18 + 123;   const int inf = (int)1e9 + 123;   const int MOD = (int)1e9 + 7;   void megaRandom() {     unsigned int FOR;     asm( rdtsc  :  =A (FOR));     srand(FOR);   }   int n;   vector<int> g[N];   long double res;   void dfs(int x, int pr = 0, int h = 1) {     if (h > 0) res += (1.0 / h);     for (auto to : g[x]) {       if (to == pr) continue;       dfs(to, x, h + 1);     }   }   int main() {     megaRandom();     cin >> n;     for (int i = 1, x, y; i < n; i++) {       cin >> x >> y;       g[x].push_back(y), g[y].push_back(x);     }     dfs(1);     cout << fixed << setprecision(6) << res;     return 0;   }   