func_code_string: #include <bits/stdc++.h>   using namespace std;   const int nsz = 5e5;   int n, rt = 1, t, l[nsz + 5], r[nsz + 5];   vector<int> g[nsz + 5];   void dfs(int u = rt, int p = rt) {     for (int i = 0; i < g[u].size(); ++i) {       int v = g[u][i];       if (v == p) continue;       l[v] = ++t;     }     r[u] = ++t;     for (int i = g[u].size() - 1; i >= 0; --i) {       int v = g[u][i];       if (v == p) continue;       dfs(v, u);     }   }   int main() {     scanf( %d , &n);     for (int i = 1; i <= n - 1; ++i) {       int u, v;       scanf( %d%d , &u, &v);       g[u].push_back(v);       g[v].push_back(u);     }     l[rt] = ++t;     dfs();     for (int u = 1; u <= n; ++u) {       cout << l[u] <<     << r[u] <<   n ;     }   }   