#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <cmath>
#include <iomanip>
#include <stack>
#include <queue>
#include <numeric>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <fstream>
#include <chrono>
#include <random>
#include <bitset>
#define rep(i,n) for(int i=0;i<(n);i++)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define sz(x) ((int)(x).size())
#define pb push_back
#define mod 1000000007
using ll = long long;
using namespace std;
ll gcd(ll a, ll b) {return b?gcd(b,a%b):a;}
ll lcm(ll a, ll b) {return a/gcd(a,b)*b;}

int main(){
  int N; cin >> N;
  vector<pair<string,string>> name(N); rep(i,N) cin >> name[i].first >> name[i].second;
  unordered_set<string> st;
  rep(i,N) {st.insert(name[i].first); st.insert(name[i].second);}
  unordered_map<string,bool> mp;
  for(auto s:st) mp[s] = true;
  rep(i,N){
    mp[name[i].first] = false;
  }
  for(auto m:mp){
    if(m.second) cout << m.first << endl;
  }
  return 0;
}