func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 2e5 + 5;   int n;   int p[N];   pair<int, int> v[N];   void solve(int nx, int nnx) {     int curr = 1;     for (int i = 1; i <= n; i++) p[i] = 0;     p[curr] = nx;     p[nx] = nnx;     curr = nx;     bool okay = true;     for (int i = 2; i <= n; i++) {       if (v[curr].first == nnx) {         if (!p[nnx]) p[nnx] = v[curr].second;         nx = nnx;         nnx = v[curr].second;         curr = nx;       } else if (v[curr].second == nnx) {         if (!p[nnx]) p[nnx] = v[curr].first;         nx = nnx;         nnx = v[curr].first;         curr = nx;       } else {         okay = false;         break;       }     }     curr = 1;     for (int i = 1; i <= n; i++) {       curr = p[curr];     }     if (curr != 1) okay = false;     if (okay) {       curr = 1;       for (int i = 1; i <= n; i++) {         printf( %d  , curr);         curr = p[curr];       }       exit(0);     }   }   int main() {     scanf( %d , &n);     for (int i = 1; i <= n; i++) {       int x, y;       scanf( %d %d , &x, &y);       v[i].first = x;       v[i].second = y;     }     solve(v[1].first, v[1].second);     solve(v[1].second, v[1].first);     return 0;   }   