Problem: One day Bob got a letter in an envelope. Bob knows that when Berland's post officers send a letter directly from city «A» to city «B», they stamp it with «A B», or «B A». Unfortunately, often it is impossible to send a letter directly from the city of the sender to the city of the receiver, that's why the letter is sent via some intermediate cities. Post officers never send a letter in such a way that the route of this letter contains some city more than once. Bob is sure that the post officers stamp the letters accurately.

There are n stamps on the envelope of Bob's letter. He understands that the possible routes of this letter are only two. But the stamps are numerous, and Bob can't determine himself none of these routes. That's why he asks you to help him. Find one of the possible routes of the letter.

Input

The first line contains integer n (1 ≤ n ≤ 105) — amount of mail stamps on the envelope. Then there follow n lines with two integers each — description of the stamps. Each stamp is described with indexes of the cities between which a letter is sent. The indexes of cities are integers from 1 to 109. Indexes of all the cities are different. Every time the letter is sent from one city to another, exactly one stamp is put on the envelope. It is guaranteed that the given stamps correspond to some valid route from some city to some other city. 

Output

Output n + 1 numbers — indexes of cities in one of the two possible routes of the letter.

Examples

Input

2
1 100
100 2


Output

2 100 1 

Input

3
3 1
100 2
3 2


Output

100 2 3 1 

Solution (in JAVA):

Solution:
//package cdr;
import java.util.*;
import java.math.*;
import java.io.*;

public class Luck{
	public static InputReader sc;
    public static PrintWriter out;
    public static final int MOD = (int) (1e9 + 7);
    public static void main(String[] args){
    	sc=new InputReader(System.in);	
    	out=new PrintWriter(System.out);
    	int n=sc.nextInt();
    	HashMap<Integer,TreeSet<Integer>> map=new HashMap<Integer,TreeSet<Integer>>();
    	TreeSet<Integer> single=new TreeSet<Integer>();
    	for(int i=0;i<n;i++){
    		int u=sc.nextInt();
    		int v=sc.nextInt();
    		if(map.containsKey(u)){
    			TreeSet<Integer> set=map.get(u);
    			set.add(v);
    			map.put(u, set);
    		}
    		else{
    			TreeSet<Integer> set=new TreeSet<Integer>();
    			set.add(v);
    			map.put(u, set);
    		}
    		if(map.containsKey(v)){
    			TreeSet<Integer> set=map.get(v);
    			set.add(u);
    			map.put(v, set);
    		}
    		else{
    			TreeSet<Integer> set=new TreeSet<Integer>();
    			set.add(u);
    			map.put(v, set);
    		}
    		if(!single.contains(u)){
    			single.add(u);
    		}
    		else{
    			single.remove(u);
    		}
    		if(!single.contains(v)){
    			single.add(v);
    		}
    		else{
    			single.remove(v);
    		}
    	}
    	int start=single.first();
    	int count=0;
    	TreeSet<Integer> visited=new TreeSet<Integer>();
    	visited.add(start);
    	while(count!=n){
    		out.print(start+" ");
    		TreeSet<Integer> set=map.get(start);
    		for(int nei:set){
    			if(visited.contains(nei)){
    				continue;
    			}
    			visited.add(nei);
    			count+=1;
    			start=nei;
    			break;
    		}
    	}
    	out.println(start);
    	out.close();
    }
    
    
   
    static int gcd(int a,int b){
    	if(b==0){
    		return a;
    	}
    	return gcd(b,a%b);
    }
    static int lcm(int a,int b){
    	int g;
    	if(a<b){
    		g=gcd(b,a);
    	}
    	else{
    		g=gcd(a,b);
    	}
    	return (a*b)/g;
    }
    
    static boolean isPrime(int n){
    	 if (n == 2)
    	        return true;
    	    for (long i = 2; i * i <= n; i++) {
    	        if (n % i == 0)
    	            return false;
    	    }
    	    return true;
    }
    
    static void shuffle(int[] A){
    	for(int i=A.length-1;i>0;i--){
    		int j=(int)(Math.random()*(i+1));
    		int temp=A[j];
    		A[j]=A[i];
    		A[i]=temp;
    	}
    }
    
	public static class Node implements Comparator<Node>{
	    int v;
	    int u;
	    public Node(){
	    	;
	    }
	    public Node (int u, int v) {
	    	this.u = u;
	        this.v = v;
	        
	    }
	    
	    public void print() {
	        out.println(v + " " + u + " ");
	    }
	    
	    public int compare(Node n1,Node n2) {
	        return n1.u-n2.u;
	    }
	}

	public static BigInteger pow(BigInteger base, BigInteger exp) {
	    if(exp.equals(new BigInteger(String.valueOf(0)))){
	        return new BigInteger(String.valueOf(1));
	    }    
	    if(exp.equals(new BigInteger(String.valueOf(1))))
	        return base;
	    BigInteger temp=exp.divide(new BigInteger(String.valueOf(2)));
	    BigInteger val = pow(base, temp);
	    BigInteger result = val.multiply(val);
	    result=result.remainder(new BigInteger(String.valueOf(MOD)));
	    BigInteger AND=exp.and(new BigInteger(String.valueOf(1)));
	    if(AND.equals(new BigInteger(String.valueOf(1)))){
	        result = result.multiply(base);
	        result=result.remainder(new BigInteger(String.valueOf(MOD)));
	    }    
	    return result;
	}
	    
	static class InputReader {

	    private InputStream stream;
	    private byte[] buf = new byte[8192];
	    private int curChar, snumChars;
	    private SpaceCharFilter filter;

	    public InputReader(InputStream stream) {
	        this.stream = stream;
	    }

	    public int snext() {
	        if (snumChars == -1)
	            throw new InputMismatchException();
	        if (curChar >= snumChars) {
	            curChar = 0;
	            try {
	                snumChars = stream.read(buf);
	            } catch (IOException e) {
	                throw new InputMismatchException();
	            }
	            if (snumChars <= 0)
	                return -1;
	        }
	        return buf[curChar++];
	    }

	    public int nextInt() {
	        int c = snext();
	        while (isSpaceChar(c))
	            c = snext();
	        int sgn = 1;
	        if (c == '-') {
	            sgn = -1;
	            c = snext();
	        }
	        int res = 0;
	        do {
	            if (c < '0' || c > '9')
	                throw new InputMismatchException();
	            res *= 10;
	            res += c - '0';
	            c = snext();
	        } while (!isSpaceChar(c));
	        return res * sgn;
	    }

	    public long nextLong() {
	        int c = snext();
	        while (isSpaceChar(c))
	            c = snext();
	        int sgn = 1;
	        if (c == '-') {
	            sgn = -1;
	            c = snext();
	        }
	        long res = 0;
	        do {
	            if (c < '0' || c > '9')
	                throw new InputMismatchException();
	            res *= 10;
	            res += c - '0';
	            c = snext();
	        } while (!isSpaceChar(c));
	        return res * sgn;
	    }

	    public int[] nextIntArray(int n) {
	        int a[] = new int[n];
	        for (int i = 0; i < n; i++)
	            a[i] = nextInt();
	        return a;
	    }

	    public String readString() {
	        int c = snext();
	        while (isSpaceChar(c))
	            c = snext();
	        StringBuilder res = new StringBuilder();
	        do {
	            res.appendCodePoint(c);
	            c = snext();
	        } while (!isSpaceChar(c));
	        return res.toString();
	    }

	    public boolean isSpaceChar(int c) {
	        if (filter != null)
	            return filter.isSpaceChar(c);
	        return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
	    }

	    public interface SpaceCharFilter {
	        public boolean isSpaceChar(int ch);
	    }
	}

}