#include<bits/stdc++.h>
#define REP(i,n) for(int i=0,i##_len=(n);i<i##_len;++i)
#define rep(i,a,b) for(int i=int(a);i<int(b);++i)
#define All(x) (x).begin(),(x).end()
using namespace std;
using ll = long long;

int main(){
    int N;cin>>N;
    vector<string> A(N),B;
    set<string> st;
    REP(i,N){
        string b;
        cin>>A[i]>>b;
        if(!st.count(b)){
            B.push_back(b);
            st.insert(b);
        }
    }
    sort(All(A));
    REP(i,B.size()){
        int k=lower_bound(All(A),B[i])-A.begin();
        if(k==N||A[k]!=B[i]){
            cout<<B[i]<<endl;
        }
    }
}