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

import java.io.*;
import java.util.*;

public class D {
	FastScanner in = new FastScanner(System.in);
	PrintWriter out = new PrintWriter(System.out);

	int getId(char a, char b) {
		int p1 = all.indexOf(a);
		int p2 = all.indexOf(b);
		int ans = p1 * all.length() + p2;
		res[0][ans] = a;
		res[1][ans] = b;
		return p1 * all.length() + p2;
	}
	
	void go(int v) {
		while (sz[v] >= 0) {
			int to = g[v].get(sz[v]);
			sz[v]--;
			go(to);
		}
		ans.add(v);
	}
	
	String all = "";
	int[] sz;
	char[][] res;
	ArrayList<Integer>[] g;
	ArrayList<Integer> ans = new ArrayList<Integer>();
	
	public void run() {
		int n = in.nextInt();
		for (int i = 0; i < 26; i++) {
			all += (char)('a' + i);
			all += (char)('A' + i);
		}
		for (int i = 0; i < 10; i++) {
			all += (char)('0' + i);
		}
		int cnt = all.length() * all.length();
		
		res = new char[2][cnt];
		g = new ArrayList[cnt];
		for (int i = 0; i < cnt; i++)
			g[i] = new ArrayList<Integer>();
		
		int[] inD = new int[cnt];
		for (int i = 0; i < n; i++) {
			String s = in.next();
			int from = getId(s.charAt(0), s.charAt(1));
			int to = getId(s.charAt(1), s.charAt(2));
			g[from].add(to);
			inD[to]++;
		}
		int start = -1, end = -1;
		for (int i = 0; i < cnt; i++) {
			if (g[i].size() == inD[i]) {
				continue;
			}
			if (Math.abs(g[i].size() - inD[i]) != 1) {
				System.out.println("NO");
				return;
			}
			if (g[i].size() > inD[i]) {
				if (start == -1) {
					start = i;
				} else {
					System.out.println("NO");
					return;
				}
			} else {
				if (end == -1) {
					end = i;
				} else {
					System.out.println("NO");
					return;
				}
			}
		}
		if (start == -1) {
			start = 0;
			while (g[start].size() == 0) {
				start++;
			}
			end = start;
		}
		
		sz = new int[cnt];
		for (int i = 0; i < cnt; i++) {
			sz[i] = g[i].size() - 1;
		}
		go(start);
		
		for (int i = 0; i < cnt; i++) {
			if (sz[i] != -1) {
				System.out.println("NO");
				return;
			}
		}
		out.println("YES");
		out.print(res[0][ans.get(ans.size() - 1)]);
		for (int i = ans.size() - 1; i >= 0; i--) {
			int cur = ans.get(i);
			out.print(res[1][cur]);
		}
		out.close();
	}

	public static void main(String[] args) {
		new D().run();
	}

	public void mapDebug(int[][] a) {
		System.out.println("--------map display---------");

		for (int i = 0; i < a.length; i++) {
			for (int j = 0; j < a[i].length; j++) {
				System.out.printf("%3d ", a[i][j]);
			}
			System.out.println();
		}

		System.out.println("----------------------------");
		System.out.println();
	}

	public void debug(Object... obj) {
		System.out.println(Arrays.deepToString(obj));
	}

	class FastScanner {
		private InputStream stream;
		private byte[] buf = new byte[1024];
		private int curChar;
		private int numChars;

		public FastScanner(InputStream stream) {
			this.stream = stream;
			//stream = new FileInputStream(new File("dec.in"));

		}

		int read() {
			if (numChars == -1)
				throw new InputMismatchException();
			if (curChar >= numChars) {
				curChar = 0;
				try {
					numChars = stream.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (numChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}

		boolean isSpaceChar(int c) {
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}

		boolean isEndline(int c) {
			return c == '\n' || c == '\r' || c == -1;
		}

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

		int[] nextIntArray(int n) {
			int[] array = new int[n];
			for (int i = 0; i < n; i++)
				array[i] = nextInt();

			return array;
		}

		int[][] nextIntMap(int n, int m) {
			int[][] map = new int[n][m];
			for (int i = 0; i < n; i++) {
				map[i] = in.nextIntArray(m);
			}
			return map;
		}

		long nextLong() {
			return Long.parseLong(next());
		}

		long[] nextLongArray(int n) {
			long[] array = new long[n];
			for (int i = 0; i < n; i++)
				array[i] = nextLong();

			return array;
		}

		long[][] nextLongMap(int n, int m) {
			long[][] map = new long[n][m];
			for (int i = 0; i < n; i++) {
				map[i] = in.nextLongArray(m);
			}
			return map;
		}

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

		double[] nextDoubleArray(int n) {
			double[] array = new double[n];
			for (int i = 0; i < n; i++)
				array[i] = nextDouble();

			return array;
		}

		double[][] nextDoubleMap(int n, int m) {
			double[][] map = new double[n][m];
			for (int i = 0; i < n; i++) {
				map[i] = in.nextDoubleArray(m);
			}
			return map;
		}

		String next() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isSpaceChar(c));
			return res.toString();
		}

		String[] nextStringArray(int n) {
			String[] array = new String[n];
			for (int i = 0; i < n; i++)
				array[i] = next();

			return array;
		}

		String nextLine() {
			int c = read();
			while (isEndline(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isEndline(c));
			return res.toString();
		}
	}
}

