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.BufferedReader;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.TreeSet;
public class Main {
//	public static int w;
//	public static int k;
//	public static int n;
//	public static int[][] dp;
//	public static int[] r;
//	public static long[] buy;
//	public static List<double[]> list = new ArrayList<double[]>();
//	public static NodeW[] product;
//	public static int[][] dists;
//	public static int x;
//	public static int[][] memo;
//	public static String str;
//	public static HashSet<String> set;
	public static void main(String[] args) throws NumberFormatException, IOException{

		ContestScanner in = new ContestScanner();
		int n = in.nextInt();
		HashMap<Integer, Integer> headmap = new HashMap<Integer, Integer>();
		HashMap<Integer, Integer> tailmap = new HashMap<Integer, Integer>();
		HashSet<Integer> idset = new HashSet<Integer>();
		for(int i=0; i<n; i++){
			int h = in.nextInt();
			int t = in.nextInt();
			headmap.put(h, t);
			tailmap.put(t, h);
			idset.add(t);
			idset.add(h);
		}
//		if(n == 2){
//			
//			return;
//		}
		
		List<Integer> list1 = new LinkedList<Integer>();
		List<Integer> list2 = new LinkedList<Integer>();
		
		int head = headmap.get(0);
		idset.remove((Integer)0);
		list1.add(head);
		tailmap.remove(head);
		idset.remove((Integer)head);
		while(headmap.containsKey(head)){
			head = headmap.get(head);
			if(head == 0) break;
			list1.add(head);
			tailmap.remove(head);
			idset.remove((Integer)head);
		}
		int rest = idset.iterator().next();
		int tail = rest;
		list2.add(tail);
		while(headmap.containsKey(tail)){
			tail = headmap.get(tail);
			if(tail == 0) break;
			list2.add(tail);
		}
		tail = rest;
		while(tailmap.containsKey(tail)){
			tail = tailmap.get(tail);
			list2.add(0, tail);
		}
		Iterator<Integer> it1 = list1.iterator();
		Iterator<Integer> it2 = list2.iterator();
		while(it1.hasNext() || it2.hasNext()){
			if(it2.hasNext()) System.out.print(it2.next()+" ");
			if(it1.hasNext()) System.out.print(it1.next()+" ");
		}
		System.out.println();
	}
	
}
//
//class MyComp implements Comparator<String>{
//	public int compare(String a, String b) {
//		return a.equals(b) ? 0 : 1;
//	}
//}


class Reverse implements Comparator<Integer>{
	public int compare(Integer arg0, Integer arg1) {
		return arg1 - arg0;
	}
}

class Node{
	int id;
	List<Node> edge = new ArrayList<Node>();
	public Node(int id){
		this.id = id;
	}
	public void createEdge(Node node){
		edge.add(node);
	}
}


class NodeW{
	int id;
//	int dist;
	List<NodeW> edge = new ArrayList<NodeW>();
	List<Integer> costList = new ArrayList<Integer>();
	public NodeW(int id) {
		this.id = id;
	}
	public void createEdge(NodeW node, int cost) {
		edge.add(node);
		costList.add(cost);
//		node.setDist(dist+1);
	}
//	public void setDist(int dist){
//		this.dist = Math.max(this.dist, dist);
//		for(NodeW node: edge){
//			node.setDist(dist+1);
//		}
//	}
}

class Range<T extends Comparable<T>> implements Comparable<Range<T>>{
	T start;
	T end;
	public Range(T start, T end){
		this.start = start;
		this.end = end;
	}
	public boolean inRange(T val){
		if(start.compareTo(val) <= 0 && end.compareTo(val) >= 0){
			return true;
		}
		return false;
	}
	
	public boolean isCommon(Range<T> range){
		if(inRange(range.start) || inRange(range.end) || range.inRange(start)){
			return true;
		}
		return false;
	}
	
	public Range<T> connect(Range<T> range){
		if(!isCommon(range)) return null;
		Range<T> res = new Range<T>(start.compareTo(range.start) <= 0 ? start : range.start,
				end.compareTo(range.end) >= 0 ? end : range.end);
		return res;
	}
	
	public boolean connectToThis(Range<T> range){
		if(!isCommon(range)) return false;
		start = start.compareTo(range.start) <= 0 ? start : range.start;
		end = end.compareTo(range.end) >= 0 ? end : range.end;
		return true;
	}
	@Override
	public int compareTo(Range<T> range) {
		int res = start.compareTo(range.start);
		if(res == 0) return end.compareTo(range.end);
		return res;
	}
	
	public String toString(){
		return "["+start+","+end+"]";
	}
}

class RangeSet<T extends Comparable<T>>{
	TreeSet<Range<T>> ranges = new TreeSet<Range<T>>();
	public void add(Range<T> range){
		Range<T> con = ranges.floor(range);
		if(con != null){
			if(con.connectToThis(range))
				range = con;
		}
		con = ranges.ceiling(range);
		while(con != null && range.connectToThis(con)){
			ranges.remove(con);
			con = ranges.ceiling(range);
		}
		ranges.add(range);
	}
	
	public String toString(){
		StringBuilder bld = new StringBuilder();
		for(Range<T> r: ranges){
			bld.append(r+"\n");
		}
		return bld.toString();
	}
}


class MyMath{
	public static long fact(long n){
		long res = 1;
		while(n > 0){
			res *= n--;
		}
		return res;
	}
	public static long[][] pascalT(int n){
		long[][] tri = new long[n][];
		for(int i=0; i<n; i++){
			tri[i] = new long[i+1];
			for(int j=0; j<i+1; j++){
				if(j == 0 || j == i){
					tri[i][j] = 1;
				}else{
					tri[i][j] = tri[i-1][j-1] + tri[i-1][j];
				}
			}
		}
		return tri;
	}
}

class ContestScanner{
	private BufferedReader reader;
	private String[] line;
	private int idx;
	public ContestScanner() throws FileNotFoundException{
		reader = new BufferedReader(new InputStreamReader(System.in));
	}
	
	public String nextToken() throws IOException{
		if(line == null || line.length <= idx){
			line = reader.readLine().trim().split(" ");
			idx = 0;
		}
		return line[idx++];
	}
	
	public long nextLong() throws IOException, NumberFormatException{
		return Long.parseLong(nextToken());
	}
	
	public int nextInt() throws NumberFormatException, IOException{
		return (int)nextLong();
	}
	
	public double nextDouble() throws NumberFormatException, IOException{
		return Double.parseDouble(nextToken());
	}
}