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.util.*;

public class _490B {

    static class Node {
        int value;
        Node head;
        Node tail;
        Node next;

        public Node(int value) {
            this.value = value;
            head = tail = this;
            next = null;
        }

        public List<Integer> toList() {
            List<Integer> list = new ArrayList<>();
            for (Node i=head; i!=null; i=i.next) {
                list.add(i.value);
            }
            return list;
        }
    }

    static final int MAX = 1111111;
    static int n;
    static int[] father = new int[MAX];
    static Node[] list = new Node[MAX];

    static {
        for (int i=0; i<father.length; i++) father[i] = i;
        for (int i = 0; i < list.length; i++) {
            list[i] = new Node(i);
        }
    }

    static int find(int i) {
        if (father[i] != i) father[i] = find(father[i]);
        return father[i];
    }

    static void union(int i, int j) {
        i = find(i);
        j = find(j);
        if (i != j) {
            father[j] = i;
            list[i].tail.next = list[j].head;
            list[i].tail = list[j].tail;
        }
    }

    public static void main(String[] args) throws Exception {
        Reader.init(System.in);
        BufferedWriter cout = new BufferedWriter(new OutputStreamWriter(System.out));

        n = Reader.nextInt();
        Set<Integer> cand = new HashSet<>();
        int second = -1;
        for (int i = 0; i < n; i++) {
            int u = Reader.nextInt();
            int v = Reader.nextInt();
            if (u == 0) second = v;
            if (u != 0 && v != 0) union(u, v);

            if (u > 0) cand.add(u);
            if (v > 0) cand.add(v);
        }

        int first = -1;
        for (int i : cand)
            if (find(i) != find(second)) {
                first = find(i);
                break;
            }

        List<Integer> a = list[find(first)].toList();
        List<Integer> b = list[find(second)].toList();
        StringBuilder ans = new StringBuilder();
        for (int i = 0, j = 0; i < a.size() || j < b.size(); ) {
            if (i < a.size()) {
                ans.append(a.get(i++));
                ans.append(' ');
            }
            if (j < b.size()) {
                ans.append(b.get(j++));
                ans.append(' ');
            }
        }

        System.out.println(ans.toString());
        cout.close();
    }

    static class Pair<U extends Comparable<U>, V extends Comparable<V>> implements Comparable<Pair<U, V>> {
        final U _1;
        final V _2;

        private Pair(U key, V val) {
            this._1 = key;
            this._2 = val;
        }

        public static <U extends Comparable<U>, V extends Comparable<V>> Pair<U, V> instanceOf(U _1, V _2) {
            return new Pair<U, V>(_1, _2);
        }

        @Override
        public String toString() {
            return _1 + " " + _2;
        }

        @Override
        public int hashCode() {
            int res = 17;
            res = res * 31 + _1.hashCode();
            res = res * 31 + _2.hashCode();
            return res;
        }

        @Override
        public int compareTo(Pair<U, V> that) {
            int res = this._1.compareTo(that._1);
            if (res < 0 || res > 0) return res;
            else return this._2.compareTo(that._2);
        }

        @Override
        public boolean equals(Object obj) {
            if (this == obj) return true;
            if (!(obj instanceof Pair)) return false;
            Pair<?, ?> that = (Pair<?, ?>) obj;
            return _1.equals(that._1) && _2.equals(that._2);
        }
    }

    /**
     * Class for buffered reading int and double values
     */
    static class Reader {
        static BufferedReader reader;
        static StringTokenizer tokenizer;

        /**
         * call this method to initialize reader for InputStream
         */
        static void init(InputStream input) {
            reader = new BufferedReader(new InputStreamReader(input));
            tokenizer = new StringTokenizer("");
        }

        /**
         * get next word
         */
        static String next() throws IOException {
            while (!tokenizer.hasMoreTokens()) {
                // TODO add check for eof if necessary
                tokenizer = new StringTokenizer(reader.readLine());
            }
            return tokenizer.nextToken();
        }

        static int nextInt() throws IOException {
            return Integer.parseInt(next());
        }

        static double nextDouble() throws IOException {
            return Double.parseDouble(next());
        }
    }

    static class ArrayUtil {
        static void swap(int[] a, int i, int j) {
            int tmp = a[i];
            a[i] = a[j];
            a[j] = tmp;
        }

        static void swap(long[] a, int i, int j) {
            long tmp = a[i];
            a[i] = a[j];
            a[j] = tmp;
        }

        static void swap(double[] a, int i, int j) {
            double tmp = a[i];
            a[i] = a[j];
            a[j] = tmp;
        }

        static void swap(char[] a, int i, int j) {
            char tmp = a[i];
            a[i] = a[j];
            a[j] = tmp;
        }

        static void swap(boolean[] a, int i, int j) {
            boolean tmp = a[i];
            a[i] = a[j];
            a[j] = tmp;
        }

        static void reverse(int[] a, int i, int j) {
            for (; i < j; i++, j--)
                swap(a, i, j);
        }

        static void reverse(long[] a, int i, int j) {
            for (; i < j; i++, j--)
                swap(a, i, j);
        }

        static void reverse(double[] a, int i, int j) {
            for (; i < j; i++, j--)
                swap(a, i, j);
        }

        static void reverse(char[] a, int i, int j) {
            for (; i < j; i++, j--)
                swap(a, i, j);
        }

        static void reverse(boolean[] a, int i, int j) {
            for (; i < j; i++, j--)
                swap(a, i, j);
        }

        static long sum(int[] a) {
            int sum = 0;
            for (int i : a)
                sum += i;
            return sum;
        }

        static long sum(long[] a) {
            long sum = 0;
            for (long i : a)
                sum += i;
            return sum;
        }

        static double sum(double[] a) {
            double sum = 0;
            for (double i : a)
                sum += i;
            return sum;
        }

        static int max(int[] a) {
            int max = Integer.MIN_VALUE;
            for (int i : a)
                if (i > max) max = i;
            return max;
        }

        static int min(int[] a) {
            int min = Integer.MAX_VALUE;
            for (int i : a)
                if (i < min) min = i;
            return min;
        }

        static long max(long[] a) {
            long max = Long.MIN_VALUE;
            for (long i : a)
                if (i > max) max = i;
            return max;
        }

        static long min(long[] a) {
            long min = Long.MAX_VALUE;
            for (long i : a)
                if (i < min) min = i;
            return min;
        }
    }
}