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
/*
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 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

//package d;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;

/**
 *
 * @author Vlad
 */
public class D {
    FastScanner in;
    private static ArrayList<String> list = new ArrayList<>();
    private static Map<String, Integer> map = new HashMap<>();
    private static Map<Integer, String> name = new HashMap<>();
    private static ArrayList<ArrayList<Integer>> input = new ArrayList<>();
    private static ArrayList<ArrayList<Integer>> output = new ArrayList<>();
    private static StringBuilder str = new StringBuilder("");
    private static int[] nommer;
    private static boolean fl = false;
    
    public void run() {
        in = new FastScanner();
        int n = in.nextInt();
        for (int i = 0; i < n; i++) {
            String s = in.nextToken();
            String a = s.substring(0, 2);
            String b = s.substring(1, 3);
            
            int noma = getNom(a);
            int nomb = getNom(b);
            name.put(noma, a);
            name.put(nomb, b);
            
            input.get(nomb).add(noma);
            output.get(noma).add(nomb);
        }
        
        int kil = 0;
        int t1 = -1;
        int t2 = -1;
        int nom = 0;
        Iterator it = map.values().iterator();
        while (it.hasNext()) {
            Integer i = (Integer) it.next();
            int to = input.get(i).size();
            int from = output.get(i).size();
            
            if (to == from) continue;
            if (to == from + 1 || to == from -1) {
                if (to == from + 1) {
                    if (t1 == -1) {
                        t1 = i;
                    } else {
                        System.out.println("NO");
                        return;
                    }
                }
                if (to == from - 1) { 
                    if (t2 == -1) {
                        nom = i; 
                        t2 = i;
                    } else {
                        System.out.println("NO");
                        return;
                    }
                }
                kil++;
            } else {
                System.out.println("NO");
                return;
            }
        }
        
        if (kil != 2 && kil != 0) {
                System.out.println("NO");
                return;
        }
  
        nommer = new int[map.size()];
        //str = new StringBuilder(name.get(nom));
        Way(nom);
        if (list.size() != n + 1) {
            System.out.println("NO");
            return;
        }
        System.out.println("YES");
        System.out.print(list.get(list.size()-1));
        for (int i = list.size()-2; i >= 0 ; i--) {
            System.out.print(list.get(i).charAt(1));
        }
        System.out.println();

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

    private static int getNom(String a) {
        if (!map.containsKey(a)) {
            int size = input.size();
            map.put(a, size);
            input.add(new ArrayList<>());
            output.add(new ArrayList<>());
            return size;
        }
        return map.get(a);
    }

    private static void Way(int nom) {
        for (; nommer[nom] < output.get(nom).size(); ) {
            int newNom = output.get(nom).get(nommer[nom]);
            nommer[nom]++;
            Way(newNom);
        }
        list.add(name.get(nom));
        
    }
    
     class FastScanner {
        BufferedReader br;
        StringTokenizer st;

        public FastScanner() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        public FastScanner(String s) {
            try {
                br = new BufferedReader(new FileReader(s));
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }
        }

        String nextToken() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

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

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

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