#include "bits/stdc++.h"
#define REP(i, n) for(int i = 0; i < int(n); i++)
#define FOR(i,n,m) for(int i = int(n); i < int(m); i++)
using namespace std;
typedef long long ll;
const int MOD = 1e9 + 7;
const int INF = 1e9 + 6;
const ll LLINF = 1e18 + 1;

int main() {
    int n; cin >> n;
    map<string, int> mp;
    vector<string> ans;
    REP(i, n) {
        string s, t; cin >> s >> t;
        if (mp.find(s) == mp.end()) ans.push_back(s);
        if (mp.find(t) == mp.end()) ans.push_back(t);
        mp[s] = -1;
        if (mp.find(t) == mp.end() || mp[t] != -1) mp[t] = 1;
    }
    REP(i, ans.size()) {
        if (mp[ans[i]] == 1) {
            cout << ans[i] << endl;
        }
    }
    return 0;
}