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 MainClass
{
    public static void main(String[] args)throws IOException
    {
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.parseInt(in.readLine());
        String[] A = new String[n];
        int total = 62 * 62;
        ArrayList<Integer>[] adj = (ArrayList<Integer>[])new ArrayList[62 * 62];
        for (int i=0;i<total;i++)
            adj[i] = new ArrayList<>();
        for (int i=0;i<n;i++)
        {
            String s = in.readLine();
            int d1 = getCode(s.charAt(0));
            int d2 = getCode(s.charAt(1));
            int d3 = getCode(s.charAt(2));
            int n1 = d1 * 62 + d2;
            int n2 = d2 * 62 + d3;
            adj[n1].add(n2);
        }
        EulerPath eulerPath = new EulerPath(total, adj);
        int[] path = eulerPath.getEulerPath();
        if (path == null)
            System.out.println("NO");
        else
        {
            StringBuilder stringBuilder = new StringBuilder();
            stringBuilder.append("YES\n");
            for (int i=0;i<path.length;i++)
            {
                if (i == 0)
                {
                    char c1 = getChar(path[i] / 62);
                    stringBuilder.append(c1);
                }
                int n1 = path[i];
                char ch = getChar(n1);
                stringBuilder.append(ch);
            }
            System.out.println(stringBuilder);
        }

    }
    public static char getChar(int code)
    {
        code %= 62;
        if (code < 10)
            return (char)('0' + code);
        else if (code < 36)
            return (char)('A' + code - 10);
        return (char)('a' + code - 36);
    }
    public static int getCode(char ch)
    {
        if (ch >= '0' && ch <= '9')
            return ch - '0';
        else if (ch >= 'A' && ch <= 'Z')
            return 10 + ch - 'A';
        else
            return 36 + ch - 'a';
    }
}
class Reader
{
    final private int BUFFER_SIZE = 1 << 16;
    private DataInputStream din;
    private byte[] buffer;
    private int bufferPointer, bytesRead;

    public Reader()
    {
        din = new DataInputStream(System.in);
        buffer = new byte[BUFFER_SIZE];
        bufferPointer = bytesRead = 0;
    }

    public Reader(String file_name) throws IOException
    {
        din = new DataInputStream(new FileInputStream(file_name));
        buffer = new byte[BUFFER_SIZE];
        bufferPointer = bytesRead = 0;
    }

    public String readLine() throws IOException
    {
        byte[] buf = new byte[64]; // line length
        int cnt = 0, c;
        while ((c = read()) != -1)
        {
            if (c == '\n')
                break;
            buf[cnt++] = (byte) c;
        }
        return new String(buf, 0, cnt);
    }

    public int nextInt() throws IOException
    {
        int ret = 0;
        byte c = read();
        while (c <= ' ')
            c = read();
        boolean neg = (c == '-');
        if (neg)
            c = read();
        do
        {
            ret = ret * 10 + c - '0';
        }  while ((c = read()) >= '0' && c <= '9');

        if (neg)
            return -ret;
        return ret;
    }

    public long nextLong() throws IOException
    {
        long ret = 0;
        byte c = read();
        while (c <= ' ')
            c = read();
        boolean neg = (c == '-');
        if (neg)
            c = read();
        do {
            ret = ret * 10 + c - '0';
        }
        while ((c = read()) >= '0' && c <= '9');
        if (neg)
            return -ret;
        return ret;
    }

    public double nextDouble() throws IOException
    {
        double ret = 0, div = 1;
        byte c = read();
        while (c <= ' ')
            c = read();
        boolean neg = (c == '-');
        if (neg)
            c = read();

        do {
            ret = ret * 10 + c - '0';
        }
        while ((c = read()) >= '0' && c <= '9');

        if (c == '.')
        {
            while ((c = read()) >= '0' && c <= '9')
            {
                ret += (c - '0') / (div *= 10);
            }
        }

        if (neg)
            return -ret;
        return ret;
    }

    private void fillBuffer() throws IOException
    {
        bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
        if (bytesRead == -1)
            buffer[0] = -1;
    }

    private byte read() throws IOException
    {
        if (bufferPointer == bytesRead)
            fillBuffer();
        return buffer[bufferPointer++];
    }

    public void close() throws IOException
    {
        if (din == null)
            return;
        din.close();
    }
}
class EulerPath
{
    private int n;
    private int edgeCount;
    private int[] in, out;
    private LinkedList<Integer> path = new LinkedList<>();
    private ArrayList<Integer>[] adj;

    public EulerPath(int n, ArrayList<Integer>[] adj)
    {
        this.n = n;
        this.adj = adj;
        in = new int[n];
        out = new int[n];
        edgeCount = 0;
        for (int i=0;i<n;i++)
        {
            out[i] = adj[i].size();
            for (int j: adj[i])
                in[j] ++;
            edgeCount += out[i];
        }
    }

    public boolean hasEulerianPath()
    {
        if (edgeCount == 0)
            return false;
        int startNodes = 0;
        int endNodes = 0;
        for (int i=0;i<n;i++)
        {
            if (out[i] - in[i] > 1 || in[i] - out[i] > 1)   return false;
            else if (out[i] - in[i] == 1)   startNodes++;
            else if (in[i] - out[i] == 1)   endNodes++;
        }
        return (endNodes == 0 && startNodes == 0) || (endNodes == 1 && startNodes == 1);
    }

    private int findStartNode()
    {
        int start = 0;
        for (int i=0;i<n;i++)
        {
            if (out[i] - in[i] == 1)
                return i;
            if (out[i] > 0)
                start = i;
        }
        return start;
    }

    public int[] getEulerPath()
    {
        if (!hasEulerianPath()) return null;
        dfs(findStartNode());

        if (path.size() != edgeCount + 1)
            return null;
        int[] soln = new int[edgeCount + 1];
        for (int i=0;!path.isEmpty();i++)
            soln[i] = path.removeFirst();
        return soln;
    }

    private void dfs(int v)
    {
        while (out[v] != 0)
        {
            int next = adj[v].get(--out[v]);
            dfs(next);
        }
        path.addFirst(v);
    }
}

