func_code_string: #include <bits/stdc++.h>   using namespace std;   int n;   int a[200000 + 5];   vector<int> g[200000 + 5];   int cnt = 0;   void dfs(int x, int fa) {     cnt++;     if (cnt > n) return;     printf( %d  , x);     for (int i = 0; i < g[x].size(); i++) {       int y = g[x][i];       if (y == fa) continue;       dfs(y, x);     }   }   int main() {     scanf( %d , &n);     int xx, yy;     for (int i = 1; i <= n; i++) {       int x, y;       scanf( %d , &x), scanf( %d , &y);       if (i == 1) xx = x, yy = y;       g[y].push_back(x), g[x].push_back(y);     }     if (g[1][0] != xx && g[1][0] != yy) swap(g[1][0], g[1][1]);     dfs(1, 0);     return 0;   }   