#include <bits/stdc++.h>

using namespace std;

#define rep(i, n) for(int i = 0; i < (int)n; ++i)
#define FOR(i, a, b) for(int i = a; i < (int)b; ++i)
#define rrep(i, n) for(int i = ((int)n - 1); i >= 0; --i)

typedef long long ll;
typedef long double ld;

const int Inf = 1e9;
const double EPS = 1e-9;
const int MOD = 1e9 + 7;

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(0);
    int n;
    cin >> n;
    map<string, int> mp;
    vector<string> p;
    rep (i, n) {
        string s, t;
        cin >> s >> t;
        mp[s]++;
        if (mp.count(t) == 0) p.push_back(t);
        mp[t]++;
        if (mp[t] == 1) mp[t] = 0;
    }
    rep (i, p.size()) {
        if (mp[p[i]] == 0) cout << p[i] << endl;
    }
    
    return 0;
}