#include<bits/stdc++.h>
#include<time.h>
using namespace std;

using ll = long long;
#define rep(i,n) for(ll i=0;i<ll(n);i++)
#define all(A) A.begin(),A.end()
using vll = vector<ll>;
using vvll = vector<vll>;
using vvvll = vector<vvll>;
using vvvvll = vector<vvvll>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vvvb = vector<vvb>;
using vvvvb = vector<vvvb>;

bool DEB = 0;

bool isbool(ll N){
    if(N<=1)return 0;
    for(ll i=2;i*i<=N;i++){
        if(N%i==0)return 0;
    }
    return 1;
}

ll modPow(ll a,ll n,ll mod){
    a%=mod;
    if(n==0)return 1;
    if(n%2==1)return (modPow(a,n-1,mod)*a)%mod;
    ll res=modPow(a,n/2,mod);
    return (res*res)%mod;
}

int main() {

    map<string,ll> S;
    vector<string> P;
    ll N;
    cin>>N;
    rep(i,N){
        string A,B;
        cin>>A>>B;
        if(!S.count(A)){
            P.push_back(A);
            S[A]=S.size();
        }
        S[A]=-1;
        if(!S.count(B)){
            P.push_back(B);
            S[B]=S.size();
        }
    }
    rep(i,P.size())if(S[P[i]]>=0)cout<<P[i]<<endl;
}