Problem: During the lunch break all n Berland State University students lined up in the food court. However, it turned out that the food court, too, has a lunch break and it temporarily stopped working.

Standing in a queue that isn't being served is so boring! So, each of the students wrote down the number of the student ID of the student that stands in line directly in front of him, and the student that stands in line directly behind him. If no one stands before or after a student (that is, he is the first one or the last one), then he writes down number 0 instead (in Berland State University student IDs are numerated from 1).

After that, all the students went about their business. When they returned, they found out that restoring the queue is not such an easy task.

Help the students to restore the state of the queue by the numbers of the student ID's of their neighbors in the queue.

Input

The first line contains integer n (2 ≤ n ≤ 2·105) — the number of students in the queue. 

Then n lines follow, i-th line contains the pair of integers ai, bi (0 ≤ ai, bi ≤ 106), where ai is the ID number of a person in front of a student and bi is the ID number of a person behind a student. The lines are given in the arbitrary order. Value 0 is given instead of a neighbor's ID number if the neighbor doesn't exist.

The ID numbers of all students are distinct. It is guaranteed that the records correspond too the queue where all the students stand in some order.

Output

Print a sequence of n integers x1, x2, ..., xn — the sequence of ID numbers of all the students in the order they go in the queue from the first student to the last one.

Examples

Input

4
92 31
0 7
31 0
7 141


Output

92 7 31 141 

Note

The picture illustrates the queue for the first sample.

<image>

Solution (in JAVA):

Solution:
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Map;
import java.util.NavigableMap;
import java.util.Scanner;
import java.util.StringTokenizer;
import java.util.TreeMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;

public class b279 {

	static class Task {		
		
		public void Solve(InputReader in, PrintWriter out)
		{
			int n=in.nextInt();
			int arr[][]=new int[n][2];
			int A[]=new int[1000001];
			Arrays.fill(A,-1);
			HashSet<Integer> hs=new HashSet<>();
			int f=0;
			int s=0;
			for(int i=0;i<n;i++)
			{
				arr[i][0]=in.nextInt();
				arr[i][1]=in.nextInt();
				A[arr[i][0]]=arr[i][1];
				hs.add(arr[i][1]);
				if(arr[i][0]==0)
				{
					s=arr[i][1];
				}
			}
			for(int i=0;i<n;i++)
			{
				if(!hs.contains(arr[i][0]))
				{
					f=arr[i][0];
					break;
				}
			}
			int ans[]=new int[200001];
			ans[0]=f;
			ans[1]=s;
			for(int i=0;i<n-2;i++)
			{
				ans[i+2]=A[ans[i]];
			}
			for(int i=0;i<n;i++)
			{
				out.print(ans[i]+" ");
			}
			
		}
	}
	
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Task solver = new Task();
        solver.Solve(in,out);
        out.close();
    }
  
    static int[][] sort2D(int arr[][]){
        Arrays.sort(arr,new java.util.Comparator<int[]>(){
        public int compare(int[] a, int[] b) {
            return Integer.compare(a[0], b[0]);
        }});
        return arr;
    }
    
	static int[] di={1,0,-1,0,1,-1,-1,1};
	static int[] dj={0,1,0,-1,1,1,-1,-1};
    
	static class point{
		int x;int y;
		public point(int x,int y){
			this.x=x;
			this.y=y;
		}
	}

    static void sort(int arr[]){
		int cnt[]=new int[(1<<16)+1];
		int ys[]=new int[arr.length];	
		for(int j=0;j<=16;j+=16){
			Arrays.fill(cnt,0);
			for(int x:arr){cnt[(x>>j&0xFFFF)+1]++;}
			for(int i=1;i<cnt.length;i++){cnt[i]+=cnt[i-1];}
			for(int x:arr){ys[cnt[x>>j&0xFFFF]++]=x;}
			{ final int t[]=arr;arr=ys;ys=t;}
		}
		if(arr[0]<0||arr[arr.length-1]>=0)return;
		int i,j,c;
		for(i=arr.length-1,c=0;arr[i]<0;i--,c++){ys[c]=arr[i];}
		for(j=arr.length-1;i>=0;i--,j--){arr[j]=arr[i];}
		for(i=c-1;i>=0;i--){arr[i]=ys[c-1-i];}
	}
    
    static int lcm(int a,int b){return a*b/gcd(a,b);}
    static int abs(int x){if(x>=0)return x;else return -x;}
    static int gcd(int a,int b){return b==0?a:gcd(b,a%b);} 
    static int min(int x,int y){return x<y?x:y;}
    static int min(int x,int y,int z){return x<y?(x<z?x:z):(y<z?y:z);}
    static int max(int x,int y){return x>y?x:y;}
    static int max(int x,int y,int z){return x>y?(x>z?x:z):(y>z?y:z);}
    
    static long lcm(long a,long b){return a*b/gcd(a,b);}
    static long abs(long x){if(x>=0)return x;else return -x;}
    static long gcd(long a,long b){return b==0?a:gcd(b,a%b);}
    static long min(long x,long y){return x<y?x:y;}
    static long min(long x,long y,long z){return x<y?(x<z?x:z):(y<z?y:z);}
    static long max(long x,long y){return x>y?x:y;}
    static long max(long x,long y,long z){return x>y?(x>z?x:z):(y>z?y:z);}
    
    static void joutArray(int arr[]){
    	for(int i=0;i<arr.length;i++){
    		System.out.print(arr[i]+" ");
    	}
    	System.out.println();
    }
    
    static void joutArray(int arr[][],int n,int m){
    	for(int i=0;i<n;i++){
    		for(int j=0;j<m;j++)
    		System.out.print(arr[i][j]+" ");
    		System.out.println();
    	}
    	System.out.println();
    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }
        
        public String nextLine() {
			String fullLine=null;
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					fullLine=reader.readLine();
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
				return fullLine;
			}
			return fullLine;
		}

        public int nextInt() {
            return Integer.parseInt(next());
        }
        
        public long nextLong() {
        	return Long.parseLong(next());
        }
        
        public double nextDouble() {
        	return Double.parseDouble(next());
        }
        
        public int[] nextIntArray(int n) {
        	int arr[]=new int[n];
        	for(int i=0;i<n;i++)
        		arr[i]=nextInt();
        	return arr;
        }
        
        public char[] nextCharArray(){
        	char arr[]=next().toCharArray();
        	return arr;
        }
        
        public HashMap<Integer,Integer> inHashMap(int n){
        	HashMap<Integer,Integer> hm=new HashMap<>();
        	for(int i=0;i<n;i++){
    			int num=nextInt();
    			hm.put(num,hm.get(num)==null?1:hm.get(num)+1);
    		}
        	return hm;
        }
     }
    
   }