#include <iostream>
#include <algorithm>
#include <iomanip>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <bitset>
#include <cmath>

static const int MOD = 1000000007;
using ll = long long;
using u32 = uint32_t;
using namespace std;

template<class T> constexpr T INF = ::numeric_limits<T>::max()/32*15+208;


int main() {
    int n;
    cin >> n;
    vector<string> a(n), b(n);
    for (int i = 0; i < n; ++i) {
        cin >> a[i] >> b[i];
    }
    int cnt = 0;
    map<string, int> id;
    map<int, string> invid;
    map<int, int> ok;
    for (int i = 0; i < n; ++i) {
        if(!id.count(a[i])){
            invid[cnt] = a[i];
            id[a[i]] = cnt++;
        }
        if(!id.count(b[i])){
            invid[cnt] = b[i];
            id[b[i]] = cnt++;
        }
        ok[id[a[i]]] -= 100000;
        ok[id[b[i]]]++;
    }
    for (auto &&i : invid) {
        if(ok[i.first] > 0){
            cout << i.second << "\n";
        }
    }
    return 0;
}