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:
/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

import java.io.*;
import java.math.BigInteger;
import java.util.*;
import java.text.*;

public class cf490B {

    static BufferedReader br;
    static Scanner sc;
    static PrintWriter out;

    public static void initA() {
        try {
            br = new BufferedReader(new InputStreamReader(System.in));
            sc = new Scanner(System.in);
            out = new PrintWriter(System.out);
        } catch (Exception e) {
        }
    }

    static boolean next_permutation(Integer[] p) {
        for (int a = p.length - 2; a >= 0; --a) {
            if (p[a] < p[a + 1]) {
                for (int b = p.length - 1;; --b) {
                    if (p[b] > p[a]) {
                        int t = p[a];
                        p[a] = p[b];
                        p[b] = t;
                        for (++a, b = p.length - 1; a < b; ++a, --b) {
                            t = p[a];
                            p[a] = p[b];
                            p[b] = t;
                        }
                        return true;
                    }
                }
            }
        }
        return false;
    }

    public static String getString() {
        try {
            return br.readLine();
        } catch (Exception e) {
        }
        return "";
    }

    public static Integer getInt() {
        try {
            return Integer.parseInt(br.readLine());
        } catch (Exception e) {
        }
        return 0;
    }

    public static Integer[] getIntArr() {
        try {
            StringTokenizer temp = new StringTokenizer(br.readLine());
            int n = temp.countTokens();
            Integer temp2[] = new Integer[n];
            for (int i = 0; i < n; i++) {
                temp2[i] = Integer.parseInt(temp.nextToken());
            }
            return temp2;
        } catch (Exception e) {
        }
        return null;
    }

    public static Long[] getLongArr() {
        try {
            StringTokenizer temp = new StringTokenizer(br.readLine());
            int n = temp.countTokens();
            Long temp2[] = new Long[n];
            for (int i = 0; i < n; i++) {
                temp2[i] = Long.parseLong(temp.nextToken());
            }
            return temp2;
        } catch (Exception e) {
        }
        return null;
    }

    public static String[] getStringArr() {
        try {
            StringTokenizer temp = new StringTokenizer(br.readLine());
            int n = temp.countTokens();
            String temp2[] = new String[n];
            for (int i = 0; i < n; i++) {
                temp2[i] = (temp.nextToken());
            }
            return temp2;
        } catch (Exception e) {
        }
        return null;
    }

    public static void print(Object a) {
        out.println(a);
    }

    public static void print(String s, Object... a) {
        out.printf(s, a);
    }

    public static int nextInt() {
        return sc.nextInt();
    }

    public static double nextDouble() {
        return sc.nextDouble();
    }

    public static void main(String[] ar) {
        initA();
        cf490B c = new cf490B();
        c.solve();
        out.flush();
    }
    int MAX = 1000 * 1000 + 5;

    void solve() {
        int n = getInt();
        Integer o[] = new Integer[1000 * 1000 + 5];
        int dpn = 1;
        int pos[] = new int[MAX];

        int ct[] = new int[MAX];
        int pos_skip[] = new int[MAX];
        int pos_dpn[] = new int[MAX];

        LinkedHashSet<Integer> tp = new LinkedHashSet<Integer>();
        Integer inp[][] = new Integer[n][];
        for (int i = 0; i < n; i++) {
            inp[i] = getIntArr();
            int a = inp[i][0], b = inp[i][1];
            ct[b]++;
            tp.add(a);
            tp.add(b);
            if (a == 0) {
                o[2] = b;
                pos[b] = 2;
            } else if (b == 0) {
                o[n - 1] = a;
                pos[a] = n - 1;
            } else {
                pos_skip[a] = b;
                pos_dpn[b] = a;
            }
        }
        /*
        print("HASIL");
        for (int j = 1; j <= n; j++) {
        print("%d ", o[j]);
        }
        print("");
         * 
         */
        int i = 2;
        Integer temp = o[i];
        //print("KERJAKAN");

        while (i + 2 <= n && temp != null) {
            i += 2;
            //print(i + " " + temp);
            o[i] = pos_skip[temp];
            temp = o[i];
            pos[temp] = i;
        }
        if (n % 2 == 0) {
            i = n - 1;
            temp = o[i];

            while (i - 2 > 0 && temp != null) {
                i -= 2;
                //print(i + " " + temp);
                o[i] = pos_dpn[temp];
                temp = o[i];
                pos[temp] = i;
            }
        } else {
            int st = 0;
            for(int j : tp){
                if(ct[j] == 0){
                    st = j;
                    break;
                }
            }
            
            o[1] = st;
            i = 1;
            temp = st;
            while(i+2<=n && o[i+2] == null && temp!=null){
                i+=2;
                o[i] = pos_skip[temp];
                temp = o[i];
                pos[temp] = i;
            }
        }
        //print("HASIL");
        for (int j = 1; j <= n; j++) {
            while (o[j] == null) {
            }
            print("%d ", o[j]);
        }
        print("");


    }
}