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.*;
import java.math.BigInteger;
import java.math.RoundingMode;
import java.text.DecimalFormat;
import java.util.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.net.ssl.SSLContext;

public class Main
{  
   static long mod=(long)(998244353);
   static int[] sieve;
   static ArrayList<Integer> primes;
   
   static class Pair
   {
	   int after;
	   int before;
   }

   public static void main(String[] args) throws java.lang.Exception
   {	  	
	     fast s = new fast();
	     PrintWriter out=new PrintWriter(System.out);
	     Scanner sc=new Scanner(System.in);
	     StringBuilder fans = new StringBuilder();

	     int n=s.nextInt();
	     
	     Pair a[]=new Pair[n];
	     int order[]=new int[n];
	     int count[]=new int[1000005];
	     int count1[]=new int[1000005];
	     
	     Arrays.fill(order, -1);
	     
	     for(int i=0;i<1000005;i++) {count[i]=0;count1[i]=0;}
	     
	     HashMap<Integer,Integer> hm=new HashMap<Integer,Integer>();
	     HashMap<Integer,Integer> hm1=new HashMap<Integer,Integer>();
	     
	     for(int i=0;i<n;i++)
	    	 {
	    		 int l=s.nextInt();
	    		 int r=s.nextInt();
	    		 
	    		 a[i]=new Pair();
	    		 
	    		 a[i].after=l;
	    		 a[i].before=r;
	    		 
	    		 if(l==0) order[1]=r;
	    		 if(r==0) order[n-2]=l;
	    		 
	    		 count[l]++;
	    		 count[r]++;
	    		 
	    		 count1[r]++;
	    		 count1[l]++;
	    		 
	    		 hm.put(l, r);
	    		 
	    	 }
	     
	     for(int i=0;i<n;i++)
	    	 {
	    		 if(count[a[i].after]==1) order[0]=a[i].after;
	    		 if(count1[a[i].before]==1) order[n-1]=a[i].before;
	    	 }
	     
	     for(int i=1;i<n-3;i++)
	    	 {
	    		order[i+1]=hm.get(order[i-1]);
	    	 }
	     
	     for(int i=0;i<n;i++) System.out.print(order[i]+" ");
   }
   
   
static class fast {   
	private InputStream i;
		private byte[]  buf = new byte[1024];
		private int curChar;
		private int numChars;
		
		//Return floor log2n
		public static int log2(int bits) // returns 0 for bits=0
			{
			    int log = 0;
			    if( ( bits & 0xffff0000 ) != 0 ) { bits >>>= 16; log = 16; }
			    if( bits >= 256 ) { bits >>>= 8; log += 8; }
			    if( bits >= 16  ) { bits >>>= 4; log += 4; }
			    if( bits >= 4   ) { bits >>>= 2; log += 2; }
			    return log + ( bits >>> 1 );
			}
		
		public static boolean next_permutation(int a[])
		   {
			   int i=0,j=0;int index=-1;	   
			   int n=a.length;
			   
			   for(i=0;i<n-1;i++)
				   if(a[i]<a[i+1]) index=i;
			   
			   if(index==-1) return false;
			   i=index;

			  
			   for(j=i+1;j<n && a[i]<a[j];j++);

			   int temp=a[i];
			   a[i]=a[j-1];
			   a[j-1]=temp;
			   	   
			   for(int p=i+1,q=n-1;p<q;p++,q--)
			   {
				   temp=a[p];
				   a[p]=a[q];
				   a[q]=temp;
			   }
			   
			   return true;
		   }
		   
		   
		public static void division(char ch[],int divisor)
		   {
			   int div=Character.getNumericValue(ch[0]); int mul=10;int remainder=0;
			   StringBuilder quotient=new StringBuilder("");
			   for(int i=1;i<ch.length;i++)
			   {
				   div=div*mul+Character.getNumericValue(ch[i]);	
				   if(div<divisor) {quotient.append("0");continue;}
				   quotient.append(div/divisor);
				   div=div%divisor;mul=10;
				   
			   } 
			   remainder=div;
			   while(quotient.charAt(0)=='0')quotient.deleteCharAt(0);	   
			   System.out.println(quotient+" "+remainder);	  
		   }
		
		public static void sieve(int size)
		{
			sieve=new int[size+1];
			
			primes=new ArrayList<Integer>();
			
			sieve[1]=1;
			
			for(int i=2;i<=Math.sqrt(size);i++)
			{
				if(sieve[i]==0)
				 {
					for(int j=i*i;j<size;j+=i) {sieve[j]=1;}
				 }
			}
			
			for(int i=2;i<=size;i++)
			{
				if(sieve[i]==0) primes.add(i);
			}
		}
		
		public static long pow(long n, long b, long MOD)
		   {
		       long x=1;long y=n; 
		       while(b > 0)
		       {
		           if(b%2 == 1)
		           {
		               x=x*y;
		               if(x>MOD) x=x%(MOD);
		           }
		           y = y*y;
		           if(y>MOD) y=y%(MOD); 
		           b >>= 1;
		       }
		       return x;
		   }


		public static long mod_inv(long n,long mod)
		{
			return pow(n,mod-2,mod);
		}
		
		 public static int upper(Integer[] a,int start,int end,int key)
		 {
			   int mid=(start+end)>>1;
			   if(start==end && a[mid]<key) {return -1;}
			   if(start>end) return -1;

			   if(a[mid]>=key && (((mid-1)>=0 && a[mid-1]<key) || (mid-1)==0)) return mid;
			   else if(a[mid]== key && (mid-1)>=0 && a[mid-1]==key) return upper(a,start,mid-1,key);   
			   else if(key>a[mid]) return upper(a,mid+1,end,key);
			   else return upper(a,start,mid-1,key);
		}
		 
		 public static int lower(int[] a,int start,int end,int key)
		 {
			   int mid=(start+end)>>1;
			   if(start==end && a[mid]>key) {return -1;}
			   if(start>end) return -1;

			   if(a[mid]<=key && (((mid+1)<a.length && a[mid+1]>key) || (mid+1)==a.length)) return mid;
			   else if(a[mid]== key && (mid+1)<a.length && a[mid+1]==key) return lower(a,mid+1,end,key);   
			   else if(key>=a[mid]) return lower(a,mid+1,end,key);
			   else return lower(a,start,mid-1,key);
		} 
		   
		public long gcd(long r,long ans)
		{
			if(r==0) return ans;
			return gcd(ans%r,r);
		}
		public fast() {
			this(System.in);
		}
		public fast(InputStream is) {
			i = is;
		}
		public int read() {
			if (numChars == -1)
				throw new InputMismatchException();
			if (curChar >= numChars) {
				curChar = 0;
				try {
					numChars = i.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (numChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}
		public String nextLine() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isEndOfLine(c));
			return res.toString();
		}
		public String nextString() {
     		int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isSpaceChar(c));
			return res.toString();
		}
		public long nextLong() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}
		public int nextInt() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}
		public boolean isSpaceChar(int c) {
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}
		public boolean isEndOfLine(int c) {
			return c == '\n' || c == '\r' || c == -1;
		}

	}	
}