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.util.LinkedList;
import java.util.ArrayList;
import java.io.InputStream;
import java.util.List;
import java.util.Scanner;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Collections;
import java.io.IOException;
import java.util.AbstractCollection;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 * @author bitver
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        TaskD solver = new TaskD();
        solver.solve(1, in, out);
        out.close();
    }
}

class TaskD {
    int[] outDeg = new int[63 * 62];
    int[] inDeg = new int[63 * 62];
    LinkedList<Integer>[] adj = new LinkedList[63 * 62];
    List<Integer> ans = new ArrayList<Integer>();

    private void dfs(int v) {
        while (adj[v] != null && !adj[v].isEmpty()) {
            int i = adj[v].poll();
            dfs(i);
        }
        ans.add(v % 62);
    }

    //10 + 52
    int toInt(char c) {
        if (Character.isDigit(c)) {
            return c - '0';
        } else if (c >= 'a' && c <= 'z') {
            return 10 + c - 'a';
        } else {
            return 36 + c - 'A';
        }
    }

    //expects single char mapping
    char toChar(int i) {
        if (i < 10) {
            return (char) ('0' + i);
        } else if (i >= 10 && i < 36) {
            return (char) ('a' + (i - 10));
        } else {
            return (char) ('A' + (i - 36));
        }
    }

    int toInt(char c1, char c2) {
        return toInt(c1) * 62 + toInt(c2);
    }

    public void solve(int testNumber, Scanner in, PrintWriter out) {
        int n = in.nextInt();

        for (int i = 0; i < n; i++) {
            String s = in.next();
            int from = toInt(s.charAt(0), s.charAt(1));
            int to = toInt(s.charAt(1), s.charAt(2));
            if (adj[from] == null) {
                adj[from] = new LinkedList<Integer>();
            }
            adj[from].add(to);
            inDeg[to]++;
            outDeg[from]++;
        }

        int start = -1;
        int dnin = 0;
        int dnout = 0;
        for (int i = 0; i < inDeg.length; i++) {
            if (outDeg[i] == inDeg[i]+1){
                start = i;
                dnin++;
            } else if (outDeg[i] + 1 == inDeg[i]){
                dnout++;
            } else if (inDeg[i] != outDeg[i]){
                dnin = 2;
            } else if (outDeg[i] > 0 && start == -1) {
                start = i;
            }
        }
        if (dnin > 1 || dnout > 1){
            out.print("NO");
            return;
        }

        dfs(start);
        ans.add(start / 62);
        Collections.reverse(ans);
        if (ans.size() != n + 2) {
            out.print("NO");
            return;
        }

        StringBuilder sb = new StringBuilder();
        for (int i : ans) {
            sb.append(toChar(i));
        }
        out.println("YES");
        out.print(sb.toString());
    }
}

