import java.io.*;
import java.util.*;

class Main {
	public static void main(String[] args) {
		new Main().run();
	}

	void run() {
	 	Scanner sc = new Scanner(System.in);
		int N=sc.nextInt();
		HashSet<String> set=new HashSet<>();
		HashSet<String> ans=new HashSet<>();

		String[] A=new String[N];
		String[] B=new String[N];
		for(int i=0;i<N;++i){
			A[i]=sc.next();
			B[i]=sc.next();
			set.add(A[i]);
		}
		for(int i=0;i<N;++i){
			if(!set.contains(A[i])&&!ans.contains(A[i])){
				System.out.println(A[i]);
				ans.add(A[i]);
			}
			if(!set.contains(B[i])&&!ans.contains(B[i])){
				System.out.println(B[i]);
				ans.add(B[i]);
			}
		}
	}

	void tr(Object... objects) {
		System.out.println(Arrays.deepToString(objects));
	}

}