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.util.Scanner;
import java.io.*;
import java.util.*;
import java.math.*;
import java.lang.*;
import static java.lang.Math.*;

public class main implements Runnable{

    static ArrayList <Integer> adj[];
    static int co=0,f=0;

    static void Check2(int n){
        adj=new ArrayList[n+1];
        for(int i=0;i<=n;i++){
            adj[i]=new ArrayList<>();
        }

    }
    static void add(int i,int j){

        adj[i].add(j);
        adj[j].add(i);
    }
    public static void main(String[] args)  {
        new Thread(null, new main(), "Check2", 1<<26).start();// to increse stack size in java
    }
    static long mod=(long)(1e9+7);
    public void run() {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
        //Scanner in=new Scanner(System.in);

        InputReader in = new InputReader(System.in);
        PrintWriter w = new PrintWriter(System.out);

int n=in.nextInt();
int a[]=new int[n];
int b[]=new int[n];
int f[]=new int[1000001];
int f3[]=new int[1000001];
int f2[]=new int[1000001];
int c[]=new int[n];

for(int i=0;i<n;i++){
    a[i]=in.nextInt();
    b[i]=in.nextInt();
    f2[b[i]]=a[i];
    f[a[i]]=b[i];
    f3[a[i]]++;
    f3[b[i]]++;
}
if(n%2==0) {
    int j = n - 2;
    int val = 0;
    while (j >= 0) {

        c[j] = f2[val];
        val = f2[val];
        j -= 2;
    }

    j = 1;
    val = 0;
    while (j < n) {

        c[j] = f[val];
        val = f[val];
        j += 2;

    }

    for (int i = 0; i < n; i++) w.print(c[i] + " ");
}
else{

    int j = n - 2;
    int val = 0;
    while (j >= 0) {

        c[j] = f2[val];
        val = f2[val];
        j -= 2;
    }

 int st=0;
    int end=0;
    for(int i=0;i<n;i++){
        if(f3[a[i]]==1)st=a[i];
        if(f3[b[i]]==1)end=b[i];
    }
    c[0]=st;
    c[n-1]=end;
   j=2;
   val=st;
   while(j<n-2){
       c[j]=f[val];
       val=f[val];


       j+=2;
   }



for(int i=0;i<c.length;i++)
w.print(c[i]+" ");
}


        w.close();
    }





    static  void dfs(int i,int v[],String p,int des,char c[]){


        if(v[i]==1)return ;
        v[i]=1;

        Iterator <Integer> it=adj[i].iterator();
        while(it.hasNext()){
            int q=it.next();
            dfs(q,v,p+c[q-1],des,c);
        }





    }


    static long power(long x,long y){
        if(y==0)return 1%mod;
        if(y==1)return x%mod;


        long res=1;
        x=x%mod;
        while(y>0){


            if((y%2)!=0){
                res=(res*x)%mod;
            }


            y=y/2;
            x=(x*x)%mod;
        }


        return res;



    }


    static  int gcd(int a,int b){

        if(b==0)return a;
        return gcd(b,a%b);
    }

    static  void sev(int a[],int n){

        for(int i=2;i<=n;i++)a[i]=i;
        for(int i=2;i<=n;i++){

            if(a[i]!=0){
                for(int j=2*i;j<=n;){

                    a[j]=0;
                    j=j+i;
                }
            }

        }

    }

    static class pair implements Comparable<pair> {

        int x,y;
        pair(int c,int d){
            x=c;
            y=d;
        }

        public int compareTo(pair o){

            return (this.x-o.x);   //sort in incrementing order w.r.t to c
        }



    }

    static class node{

        int y;
        int val;

        node(int a,int b){

            y=a;
            val=b;

        }


    }
    static  void rec(String s,int a,int b,int n){

        if(b==n){
            System.out.println(s);
            return ;
        }
        String p=s;
        if(a>b){
            s=p+")" ;
            rec(s,a,b+1,n);
        }
        if(a<n){
            s=p+"(";
            rec(s,a+1,b,n);
        }




    }

    static class InputReader
    {
        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private SpaceCharFilter filter;

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

        public int read()
        {
            if (numChars==-1)
                throw new InputMismatchException();

            if (curChar >= numChars)
            {
                curChar = 0;
                try
                {
                    numChars = stream.read(buf);
                }
                catch (IOException e)
                {
                    throw new InputMismatchException();
                }

                if(numChars <= 0)
                    return -1;
            }
            return buf[curChar++];
        }

        public String nextLine()
        {
            BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
        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 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 double nextDouble()
        {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            int sgn = 1;
            if (c == '-')
            {
                sgn = -1;
                c = read();
            }
            double res = 0;
            while (!isSpaceChar(c) && c != '.')
            {
                if (c == 'e' || c == 'E')
                    return res * Math.pow(10, nextInt());
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = read();
            }
            if (c == '.')
            {
                c = read();
                double m = 1;
                while (!isSpaceChar(c))
                {
                    if (c == 'e' || c == 'E')
                        return res * Math.pow(10, nextInt());
                    if (c < '0' || c > '9')
                        throw new InputMismatchException();
                    m /= 10;
                    res += (c - '0') * m;
                    c = read();
                }
            }
            return res * sgn;
        }

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

        public String next()
        {
            return readString();
        }

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







}