#include <bits/stdc++.h>
using namespace std;
bool f1(pair<long long, long long> x, pair<long long, long long> y) {
  return x.first < y.first;
}
bool f2(pair<long long, long long> x, pair<long long, long long> y) {
  return x.first > y.first;
}
bool f3(long long x, long long y) { return x > y; }
long long gcd(long long x, long long y) {
  if (x == 0) return y;
  return gcd(y % x, x);
}
long long powmod(long long x, long long y, long long m) {
  if (y == 0) return 1;
  long long p = powmod(x, y / 2, m) % m;
  p = (p * p) % m;
  return (y % 2 == 0) ? p : (x * p) % m;
}
long long modif(long long x, long long m) { return (powmod(x, m - 2, m)); }
bool fa(vector<long long> x, vector<long long> y) { return x[0] < y[0]; }
bool fs(vector<long long> x, vector<long long> y) {
  return x.size() > y.size();
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long n;
  cin >> n;
  map<long long, long long> vis;
  map<long long, vector<long long> > r;
  for (int i = 0; i < n; i++) {
    long long x, y;
    cin >> x >> y;
    vis[x] = 0;
    vis[y] = 0;
    r[x].push_back(y);
    r[y].push_back(x);
  }
  long long st = 0;
  for (auto x : r) {
    if (x.second.size() == 1) {
      st = x.first;
      break;
    }
  }
  vector<long long> ans;
  ans.push_back(st);
  vis[st] = 1;
  for (;;) {
    for (auto y : r[st]) {
      if (!vis[y]) {
        vis[y] = 1;
        ans.push_back(y);
        st = y;
        goto p;
      }
    }
    break;
  p:;
  }
  for (auto x : ans) {
    cout << x << " ";
  }
  return 0;
}
