Problem: One day Bob got a letter in an envelope. Bob knows that when Berland's post officers send a letter directly from city «A» to city «B», they stamp it with «A B», or «B A». Unfortunately, often it is impossible to send a letter directly from the city of the sender to the city of the receiver, that's why the letter is sent via some intermediate cities. Post officers never send a letter in such a way that the route of this letter contains some city more than once. Bob is sure that the post officers stamp the letters accurately.

There are n stamps on the envelope of Bob's letter. He understands that the possible routes of this letter are only two. But the stamps are numerous, and Bob can't determine himself none of these routes. That's why he asks you to help him. Find one of the possible routes of the letter.

Input

The first line contains integer n (1 ≤ n ≤ 105) — amount of mail stamps on the envelope. Then there follow n lines with two integers each — description of the stamps. Each stamp is described with indexes of the cities between which a letter is sent. The indexes of cities are integers from 1 to 109. Indexes of all the cities are different. Every time the letter is sent from one city to another, exactly one stamp is put on the envelope. It is guaranteed that the given stamps correspond to some valid route from some city to some other city. 

Output

Output n + 1 numbers — indexes of cities in one of the two possible routes of the letter.

Examples

Input

2
1 100
100 2


Output

2 100 1 

Input

3
3 1
100 2
3 2


Output

100 2 3 1 

Solution (in JAVA):

Solution:


import java.awt.Point;
import java.io.*;
import java.math.BigInteger;
import java.util.*;

import static java.lang.Math.*;

public class ProblemC_29 {
	
	final boolean ONLINE_JUDGE = System.getProperty("ONLINE_JUDGE")!=null;
	BufferedReader in;
	PrintWriter out;
	StringTokenizer tok = new StringTokenizer("");
	
	void init() throws FileNotFoundException{
		if (ONLINE_JUDGE){
			in = new BufferedReader(new InputStreamReader(System.in));
			out = new PrintWriter(System.out);
		}else{
			in = new BufferedReader(new FileReader("input.txt"));
			out = new PrintWriter("output.txt");
		}
	}
	
	String readString() throws IOException{
		while(!tok.hasMoreTokens()){
			tok = new StringTokenizer(in.readLine());
		}
		return tok.nextToken();
	}
	
	int readInt() throws IOException{
		return Integer.parseInt(readString());
	}
	
	long readLong() throws IOException{
		return Long.parseLong(readString());
	}
	
	double readDouble() throws IOException{
		return Double.parseDouble(readString());
	}
	
	public static void main(String[] args){
		new ProblemC_29().run();
	}
	
	public void run(){
		try{
			long t1 = System.currentTimeMillis();
			init();
			solve();
			out.close();
			long t2 = System.currentTimeMillis();
			System.err.println("Time = "+(t2-t1));
		}catch (Exception e){
			e.printStackTrace(System.err);
			System.exit(-1);
		}
	}
	
	ArrayList<Point>[] graph;
	boolean[] used;
	
	void solve() throws IOException{
		int n = readInt();
		graph = new ArrayList[n+1];
		for (int i = 0; i < n + 1; i++){
			graph[i] = new ArrayList<Point>();
		}
		HashMap<Integer, Integer> map = new HashMap<Integer, Integer>();
		HashMap<Integer, Integer> map2 = new HashMap<Integer, Integer>();
		while (n-- > 0){
			int from = readInt();
			if (map.get(from) == null){
				map.put(from, map.size());
				map2.put(map2.size(), from);
			}
			int to = readInt();
			if (map.get(to) == null){
				map.put(to, map.size());
				map2.put(map2.size(), to);
			}
			graph[map.get(from)].add(new Point(map.get(to), to));
			graph[map.get(to)].add(new Point(map.get(from), from));
		}
		used = new boolean[graph.length];
		for (int i = 0; i < graph.length; i++){
			if (graph[i].size() == 1){
				dfs(new Point(i, map2.get(i)));
				return;
			}
		}
	}
	
	void dfs(Point from){
		out.print(from.y + " ");
		used[from.x] = true;
		for (Point p: graph[from.x]){
			if (!used[p.x]) dfs(p);
		}
	}
	
	static int[][] step8 = {{-1, 0}, {1, 0}, {0, -1}, {0, 1}, {-1, -1}, {1, -1}, {-1, 1}, {1, 1}};
	
	static int[][] stepKnight = {{-2, -1}, {-2, 1}, {-1, -2}, {-1, 2}, {1, -2}, {1, 2}, {2, -1}, {2, 1}};
	
	static long gcd(long a, long b){
		if (a == 0)	return b;
		return gcd(b % a, a);
	}
	
	static long lcm(long a, long b){
		return a / gcd(a, b)*b;
	}

	static long[] gcdPlus(long a, long b){
		long[] d = new long[3];
		if (a == 0){
			d[0] = b;
			d[1] = 0;
			d[2] = 1;
		}else{
			d = gcdPlus(b % a, a);
			long r = d[1];
			d[1] = d[2] - b/a*d[1];
			d[2] = r;
		}
		return d;
	}
	
	static long binpow(long a, int n){
		if (n == 0)	return 1;
		if ((n & 1) == 0){
			long b = binpow(a, n/2);
			return b*b;
		}else return binpow(a, n - 1)*a;
	}
	
	static long binpowmod(long a, int n, long m){
		if (m == 1) return 0;
		if (n == 0)	return 1;
		if ((n & 1) == 0){
			long b = binpowmod(a, n/2, m);
			return (b*b) % m;
		}else return binpowmod(a, n - 1, m)*a % m;
	}
	
	static long phi(long n){
		int[] p = Sieve((int)ceil(sqrt(n)) + 2);
		long phi = 1;
		for (int i = 0; i < p.length; i++){
			long x = 1;
			while (n % p[i] == 0){
				n /= p[i];
				x *= p[i];
			}
			phi *= x - x/p[i];
		}
		if (n != 1) phi *= n - 1;
		return phi;
	}
	
	static long f(long n, int x, int k){ //���-�� ���������� ����� (������� 0), ���������� � ���� ����� �� 0 �� k-1
		if (n == 0)	return 1;
		long b = binpow(10, x - 1);
		long c = n / b;
		return (c < k? c: k)*binpow(k, x - 1) + (c < k? 1: 0)*f(n % b, x - 1, k);
	}
	
	static long fib(int n){
		if (n == 0) return 0;
		if ((n & 1) == 0){
			long f1 = fib(n/2 - 1);
			long f2 = fib(n/2 + 1);
			return f2*f2 - f1*f1;
		}else{
			long f1 = fib(n/2);
			long f2 = fib(n/2 + 1);
			return f1*f1 + f2*f2;
		}
	}
	
	static BigInteger BigFib(int n){
		if (n == 0) return BigInteger.ZERO;
		if ((n & 1) == 0){
			BigInteger f1 = BigFib(n/2 - 1);
			f1 = f1.multiply(f1);
			BigInteger f2 = BigFib(n/2 + 1);
			f2 = f2.multiply(f2);
			return f2.subtract(f1);
		}else{
			BigInteger f1 = BigFib(n/2);
			f1 = f1.multiply(f1);
			BigInteger f2 = BigFib(n/2 + 1);
			f2 = f2.multiply(f2);
			return f2.add(f1);
		}
	}
	
	static public class PointD{
		
		double x, y;
		
		public PointD(double x, double y){
			this.x = x;
			this.y = y;
		}
	}
	
	static double d(Point p1, Point p2){
		return sqrt(d2(p1, p2));
	}
	
	static public double d(PointD p1, PointD p2){
		return sqrt(d2(p1, p2));
	}
	
	static double d2(Point p1, Point p2){
		return (p1.x - p2.x) * (p1.x - p2.x) + (p1.y - p2.y) * (p1.y - p2.y);
	}
	
	static public double d2(PointD p1, PointD p2){
		return (p1.x - p2.x) * (p1.x - p2.x) + (p1.y - p2.y) * (p1.y - p2.y);
	}
	
	static boolean IsProbablyPrime(long n){
		if (n == 1)	return false;
		if ((n & 1) == 0) return false;
		for (int j = 3; j < sqrt(n) + 1; j += 2){
			if (n % j == 0)	return false;
		}
		return true;
	}

	static int[] Sieve(int n){
		boolean[] b = new boolean[n+1];
		Arrays.fill(b, true);
		b[0] = false;
		b[1] = false;
		long nLong = n;
		int j=0;
		for (int i = 1; i <= n; i++) {
			if (b[i]){
				j++;
				if (((long)i)*i <= nLong) {
					for (int k = i*i; k <= n; k += i) {
						b[k] = false;
					}
				}
			}
		}
		int[] p = new int[j];
		Arrays.fill(p, 0);
		j=0;
		for (int i = 2; i <= n; i++) {
			if (b[i]){
				p[j]=i;
				j++;
			}
		}
		return p;
	}
	
	static int[][] Palindromes(String s){
		char[] c = s.toCharArray();
		int n = c.length;
		int[][] d = new int[2][n];
		int l = 0, r = -1;
		for (int i = 0; i < n; i++){
			int j = (i > r? 0: min(d[0][l+r-i+1], r-i+1)) + 1;
			for (; i - j >= 0 && i + j - 1< n && c[i-j] == c[i+j-1]; j++);
			d[0][i] = --j;
			if (i + d[0][i] - 1 > r){
				r = i + d[0][i] - 1;
				l = i - d[0][i];
			}
		}
		l = 0;
		r = -1;
		for (int i = 0; i < n; i++){
			int j = (i > r? 0: min(d[1][l+r-i], r-i)) + 1;
			for (; i - j >= 0 && i + j < n && c[i-j] == c[i+j]; j++);
			d[1][i] = --j;
			if (i + d[1][i] > r){
				r = i + d[1][i];
				l = i - d[1][i];
			}
		}
		return d;
	}
	
	static public class Permutation {
		
		int[] a;
		int n;
		
		public Permutation(int n){
			this.n=n;
			a=new int[n];
			for (int i=0; i<n; i++){
				a[i]=i;
			}
		}
		
		public boolean nextPermutation(){ //������� � do{}while(nextPermutation(a));
			int i=n-1;
			for (i=n-2; i>=0; i--){
				if (a[i]<a[i+1]){
					break;
				}
			}
			if (i==-1){
				return false;
			}
			int jMin=i+1;
			for (int j=n-1; j>i; j--){
				if (a[i]<a[j]&&a[j]<a[jMin]){
					jMin=j;
				}
			}
			swap(i, jMin);
			for (int j=1; j<=(n-i)/2; j++){
				swap(i+j, n-j);
			}
			return true;
		}
		
		
		public int get(int i){
			return a[i];
		}
		
		void swap(int i, int j){
			int r=a[i];
			a[i]=a[j];
			a[j]=r;
		}
	}
	
	static public class Fraction implements Comparable<Fraction>, Cloneable{
		
		public final Fraction FRACTION_ZERO = new Fraction();
		public final Fraction FRACTION_ONE = new Fraction(1);
		public long numerator = 0;
		public long denominator = 1;
		
		public Fraction(){
			numerator = 0;
			denominator = 1;
		}
		
		public Fraction(long numerator){
			this.numerator = numerator;
			denominator = 1;
		}
		
		public Fraction(long numerator, long denominator){
			this.numerator = numerator;
			this.denominator = denominator;
			Cancellation();
		}
		
		public Fraction(double numerator, double denominator, int accuracy){
			this.numerator = (long)(numerator*pow(10,accuracy));
			this.denominator = (long)(denominator*pow(10,accuracy));
			Cancellation();
		}
		
		public Fraction(String s){
			if (s.charAt(0) == '-'){
				denominator = -1;
				s = s.substring(1);
			}
			if (s.indexOf("/") != -1){
				denominator *= Integer.parseInt(s.substring(s.indexOf("/") + 1));
			}
			if (s.indexOf(" ") != -1){
				numerator = Integer.parseInt(s.substring(0, s.indexOf(" "))) * abs(denominator) + Integer.parseInt(s.substring(s.indexOf(" ") + 1, s.indexOf("/")));
			}else{
				if (s.indexOf("/") != -1){
					numerator = Integer.parseInt(s.substring(0, s.indexOf("/")));
				}else{
					numerator = Integer.parseInt(s)*abs(denominator);
				}
			}
			this.Cancellation();
		}
		
		void Cancellation(){
			long g = gcd(abs(numerator), abs(denominator));
			numerator /= g;
			denominator /= g;
			if (denominator < 0){
				numerator *= -1;
				denominator *= -1;
			}
		}
		
		public String toString(){
			String s = "";
			if (numerator == 0){
				return "0";
			}
			if (numerator < 0){
				s += "-";
			}
			if (abs(numerator) >= denominator){
				s += Long.toString(abs(numerator) / denominator) + " ";
			}
			if (abs(numerator) % denominator != 0){
				s += Long.toString(abs(numerator) % denominator);
			}else{
				s = s.substring(0, s.length()-1);
			}
			if (denominator != 1){
				s += "/" + Long.toString(denominator);
			}
			return s;
		}
		
		public Fraction add(Fraction f){
			Fraction fResult = new Fraction();
			fResult.denominator = lcm(denominator, f.denominator);
			fResult.numerator = numerator * fResult.denominator / denominator + f.numerator * fResult.denominator / f.denominator;
			fResult.Cancellation();
			return fResult;
		}
		
		public Fraction subtract(Fraction f){
			Fraction fResult = new Fraction();
			fResult.denominator = lcm(denominator, f.denominator);
			fResult.numerator = numerator * fResult.denominator / denominator - f.numerator * fResult.denominator / f.denominator;
			fResult.Cancellation();
			return fResult;
		}
		
		public Fraction multiply(Fraction f){
			Fraction fResult = new Fraction();
			fResult.numerator = numerator * f.numerator;
			fResult.denominator = denominator * f.denominator;
			fResult.Cancellation();
			return fResult;
		}
		
		public Fraction divide(Fraction f){
			Fraction fResult = new Fraction();
			fResult.numerator = numerator * f.denominator;
			fResult.denominator = denominator * f.numerator;
			fResult.Cancellation();
			return fResult;
		}
		
		@Override
		public int compareTo(Fraction f){
			long g = gcd(denominator, f.denominator);
			long res = numerator * (f.denominator / g) - f.numerator * (denominator / g);
			if (res < 0){
				return -1;
			}
			if (res > 0){
				return 1;
			}
			return 0;
		}
		
		public Fraction clone(){
			Fraction fResult = new Fraction(numerator, denominator);
			return fResult;
		}
		
		public Fraction floor(){
			Fraction fResult = this.clone();
			fResult.numerator = (fResult.numerator / fResult.denominator) * fResult.denominator;
			return fResult;
		}
		
		public Fraction ceil(){
			Fraction fResult = this.clone();
			fResult.numerator = (fResult.numerator/fResult.denominator + 1) * fResult.denominator;
			return fResult;
		}
		
		public Fraction binpow(int n){
			if (n==0) return FRACTION_ONE;
			if ((n&1)==0){
				Fraction f=this.binpow(n/2);
				return f.multiply(f);
			}else return binpow(n-1).multiply(this);
		}
	}
	
	static public class FenwickTree_1{	//One-dimensional array		
		
		int n;
		long[] t;
		
		public FenwickTree_1(int n){
			this.n = n;
			t = new long[n];
		}
		
		public long sum(int xl, int xr){
			return sum(xr) - sum(xl);
		}
		
		public long sum(int x){
			long result = 0;
			for (int i = x; i >= 0; i = (i & (i + 1)) - 1){
				result += t[i];
			}
			return result;
		}
		
		public void update(int x, long delta){
			for (int i = x; i < n; i = (i | (i + 1))){
				t[i] += delta;
			}
		}
	}
	
	static public class FenwickTree_2{	//Two-dimensional array
		
		int n, m;
		long[][] t;
		
		public FenwickTree_2(int n, int m){
			this.n = n;
			this.m = m;
			t = new long[n][m];
		}
		
		public long sum(int xl, int yl, int xr, int yr){
			return sum(xr, yr) - sum(xl - 1, yr) - sum(xr, yl - 1) + sum(xl - 1, yl - 1);
		}
		
		public long sum(int x, int y){
			long result = 0;
			for (int i = x; i >= 0; i = (i & (i + 1)) - 1){
				for (int j = y; j >= 0; j = (j & (j + 1)) - 1){
					result+=t[i][j];
				}
			}
			return result;
		}
		
		public void update(int x, int y, long delta){
			for (int i = x; i < n; i = (i | (i + 1))){
				for (int j = y; j < m; j = (j | (j + 1))){
					t[i][j] += delta;
				}
			}
		}
	}
	
	static public class FenwickTree_3{	//Three-dimensional array
		
		int n, m, l;
		long[][][] t;
		
		public FenwickTree_3(int n, int m, int l){
			this.n = n;
			this.m = m;
			this.l = l;
			t = new long[n][m][l];
		}
		
		public long sum(int xl, int yl, int zl, int xr, int yr, int zr){
			return sum(xr, yr, zr) - sum(xl - 1, yr, zr)
			+ sum(xl - 1, yr, zl - 1) - sum(xr, yr, zl - 1)
			- sum(xr, yl - 1, zr) + sum(xl - 1, yl - 1, zr)
			- sum(xl - 1, yl - 1, zl - 1) + sum(xr, yl - 1, zl - 1);
		}
		
		public long sum(int x, int y, int z){
			long result = 0;
			for (int i = x; i >= 0; i = (i & (i + 1)) - 1){
				for (int j = y; j >= 0; j = (j & (j + 1)) - 1){
					for (int k = z; k >= 0; k = (k & (k + 1)) - 1){
						result += t[i][j][k];
					}
				}
			}
			return result;
		}
		
		public void update(int x, int y, int z, long delta){
			for (int i = x; i < n; i = (i | (i + 1))){
				for (int j = y; j < n; j = (j | (j + 1))){
					for (int k = z; k < n; k = (k | (k + 1))){
						t[i][j][k] += delta;
					}
				}
			}
		}
	}
}