While dad was at work, a little girl Tanya decided to play with dad's password to his secret database. Dad's password is a string consisting of n + 2 characters. She has written all the possible n three-letter continuous substrings of the password on pieces of paper, one for each piece of paper, and threw the password out. Each three-letter substring was written the number of times it occurred in the password. Thus, Tanya ended up with n pieces of paper.

Then Tanya realized that dad will be upset to learn about her game and decided to restore the password or at least any string corresponding to the final set of three-letter strings. You have to help her in this difficult task. We know that dad's password consisted of lowercase and uppercase letters of the Latin alphabet and digits. Uppercase and lowercase letters of the Latin alphabet are considered distinct.

Input

The first line contains integer n (1 ≤ n ≤ 2·105), the number of three-letter substrings Tanya got. 

Next n lines contain three letters each, forming the substring of dad's password. Each character in the input is a lowercase or uppercase Latin letter or a digit.

Output

If Tanya made a mistake somewhere during the game and the strings that correspond to the given set of substrings don't exist, print "NO". 

If it is possible to restore the string that corresponds to given set of substrings, print "YES", and then print any suitable password option.

Examples

Input

5
aca
aba
aba
cab
bac


Output

YES
abacaba


Input

4
abc
bCb
cb1
b13


Output

NO


Input

7
aaa
aaa
aaa
aaa
aaa
aaa
aaa


Output

YES
aaaaaaaaa
/* 
 * This time without recursion
 * ACM no like java's recursion....that's so racist :(
 */

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.sql.Date;
import java.text.DateFormat;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.LinkedList;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.TimeZone;

import javax.naming.LinkLoopException;

public class Main
{

	public static void main(String[] args) throws IOException
	{
		Main main = new Main();
		main.read();
	}

	/* IO */
	private StringBuilder ans;
	private BufferedReader in;
	private StringTokenizer tok;

	/* fields */
	final int nAlpha = 26 * 2;
	final int nNums = 10;
	final int nId = (nAlpha + nNums);
	private Node[][] nodes;
	private StringBuilder originalString;

	private void read() throws IOException
	{
		// streams
		boolean file = false;
		if (file)
			in = new BufferedReader(new FileReader("input.txt"));
		else
			in = new BufferedReader(new InputStreamReader(System.in));
		ans = new StringBuilder();

		// make nodes
		nodes = new Node[nId][nId];
		for (int i = 0; i < nId; i++)
			for (int j = 0; j < nId; j++)
				nodes[i][j] = new Node(i, j);

		// make edges
		int nStrings = Integer.parseInt(in.readLine());
		for (int i = 0; i < nStrings; i++)
		{
			String str = in.readLine();
			Node source = getnode(str.charAt(0), str.charAt(1));
			Node dest = getnode(str.charAt(1), str.charAt(2));
			source.next.add(dest);
			dest.prev.add(source);
		}

		// find the starting node
		Node source = null;
		int nOdd1 = 0;
		int nOdd2 = 0;
		for (int i = 0; i < nId; i++)
			for (int j = 0; j < nId; j++)
			{
				Node node = nodes[i][j];
				if (node.next.size() == node.prev.size() + 1)
				{
					nOdd1++;
					source = node;
				} else if (node.prev.size() == node.next.size() + 1)
				{
					nOdd2++;
				} else if (node.prev.size() == node.next.size())
				{
					if (source == null && node.next.size() > 0)
						source = node;
				} else
				{
					System.out.println("NO");
					return;
				}
			}
		if (nOdd1 == 1 && nOdd2 == 1)
			;
		else if (nOdd1 == 0 && nOdd2 == 0)
			;
		else
		{
			System.out.println("NO");
			return;
		}

		// make answer
		originalString = new StringBuilder();
		dfs(source);
		originalString.append(getChar(source.id1));
		originalString.reverse();
		if (originalString.length() != nStrings + 2)
		{
			System.out.println("NO");
			return;
		}

		// output
		ans.append("YES\n");
		ans.append(originalString.toString());
		System.out.print(ans.toString());

	}

	private void dfs(Node source)
	{
		Stack<Node> s = new Stack<>();
		s.push(source);

		while (!s.isEmpty())
		{
			Node node = s.peek();
			if (node.next.size() == 0)
			{
				s.pop();
				originalString.append(getChar(node.id2));
			} else
				s.push(node.next.removeFirst());
		}
	}

	private char getChar(int id)
	{
		if (id >= 0 && id < 26)
			return (char) ('A' + id);
		else if (id >= 26 && id < 26 + 26)
			return (char) ('a' + id - 26);
		else
			return (char) ('0' + id - 26 - 26);
	}

	private Node getnode(char c1, char c2)
	{
		// get ids
		int id1 = getId(c1);
		int id2 = getId(c2);
		return nodes[id1][id2];
	}

	private int getId(char c)
	{
		if (c >= 'A' && c <= 'Z')
			return c - 'A';
		else if (c >= 'a' && c <= 'z')
			return 26 + (c - 'a');
		else if (c >= '0' && c <= '9')
			return 26 + 26 + (c - '0');
		else
			return 1 / 0;
	}

}

class Node
{
	int id1;
	int id2;
	LinkedList<Node> next;
	LinkedList<Node> prev;

	public Node(int id1, int id2)
	{
		this.id1 = id1;
		this.id2 = id2;
		this.next = new LinkedList<>();
		this.prev = new LinkedList<>();
	}

}