creed_program

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

public class MyClass {
    public static void main(String args[]) {
       new MyClass();
    }

    Scanner sc;
    int n=0;
    String inputs[][];
    ArrayList<String> result = new ArrayList();
    public MyClass(){
        sc = new Scanner(System.in);
        inputs = getInputs();
        process();
    }


    void process(){
        result.add(inputs[0][0]);
        result.add(inputs[0][1]);
        for(int j=0;j<n;j++){
            for(int i=1;i<n;i++){

                if(result.contains(inputs[i][1])){
                    int index = result.indexOf(inputs[i][1]);
                    result.add(index,inputs[i][0]);
                    inputs[i][0] = null;
                    inputs[i][1] = null;
                } else if(result.contains(inputs[i][0])){
                    int index = result.indexOf(inputs[i][0]);
                    result.add(index+1,inputs[i][1]);
                    inputs[i][0] = null;
                    inputs[i][1] = null;
                }


            }
        }

        for(int i=0;i<result.size();i++){
            System.out.print(result.get(i)+" ");
        }

    }


    String[][] getInputs(){
        String inputs[][] = new String[100][2];
        while(sc.hasNextLine()){
            String line = sc.nextLine();
            inputs[n] = line.split(" ");
            n++;
        }

        return inputs;

    }

}

/*

Bane Chris
Rafael Boris
Gregory Oliver
Boris Bane
Chris Gregory

*/