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 tanyapass {
  private static Reader in;
  private static PrintWriter out;
  
  public static int getIdx(char c) {
    if (c >= 'a' && c <= 'z') return c-'a';
    if (c >= 'A' && c <= 'Z') return c-'A'+26;
    return c-'0'+52;
  }
  public static char getChar(int idx) {
    if (idx < 26) return (char)(idx+'a');
    if (idx < 52) return (char)(idx-26+'A');
    return (char)(idx-52+'0');
  }

  public static void main(String[] args) throws IOException {
    in = new Reader();
    out = new PrintWriter(System.out, true);
    int N = in.nextInt();
    int sz = 70*70;
    int[][] grid = new int[sz][sz];
    int[] indeg = new int[sz], outdeg = new int[sz];
    for (int i = 0; i < N; i++) {
      char[] q = in.next().toCharArray();
      int a1 = getIdx(q[0])*70 + getIdx(q[1]);
      int a2 = getIdx(q[1])*70 + getIdx(q[2]);
      grid[a1][a2]++;
      indeg[a2]++;
      outdeg[a1]++;
    }
    
    boolean ok = true;
    int nonzero = -1;
    int start = -1, end = -1;
    for (int i = 0; i < sz; i++) {
      if (indeg[i] == outdeg[i]+1) {
        if (end != -1) ok = false;
        end = i;
      } else if (outdeg[i] == indeg[i]+1) {
        if (start != -1) ok = false;
        start = i;
      } else if (outdeg[i] != indeg[i]) {
        ok = false;
      }
      
      if (indeg[i] > 0) nonzero = i;
    }
    
    if (!ok) {
      out.println("NO");
      out.close();
      System.exit(0);
    }
    
    if (start == -1) {
      start = end = nonzero;
    }
    
    int[] fstack = new int[2*N];
    int[] bstack = new int[2*N];
    int fid = 0, bid = 0;
    fstack[fid++] = start;
    while (true) {
      int cur = fstack[fid-1];
      boolean found = false;
      for (int i = 0; i < sz; i++) {
        if (grid[cur][i] > 0) {
          grid[cur][i]--;
          fstack[fid++] = i;
          found = true;
          break;
        }
      }
      if (!found) break;
    }
    
    while (fid > 0) {
      int node = fstack[--fid];
      bstack[bid++] = node;
      if (fid > 0) while (true) {
        int cur = fstack[fid-1];
        boolean found = false;
        for (int i = 0; i < sz; i++) {
          if (grid[cur][i] > 0) {
            grid[cur][i]--;
            fstack[fid++] = i;
            found = true;
            break;
          }
        }
        if (!found) break;
      }
    }
    if (bid < N) {
      out.println("NO");
      out.close();
      System.exit(0);
    }
    
    char[] s = new char[N+2];
    s[0] = getChar(start/70);
    s[1] = getChar(start%70);
    for (int i = N-1; i >= 0; i--) {
      int node = bstack[i];
      s[N-i+1] = getChar(node%70);
    }
    out.println("YES");
    out.println(new String(s));
    out.close();
    System.exit(0);
  }

  static 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[1024];
      int cnt = 0;
      byte c = read();
      while (c <= ' ')
        c = read();
      do {
        buf[cnt++] = c;
      } while ((c = read()) != '\n');
      return new String(buf, 0, cnt);
    }

    public String next() throws IOException {
      byte[] buf = new byte[1024];
      int cnt = 0;
      byte c = read();
      while (c <= ' ')
        c = read();
      do {
        buf[cnt++] = c;
      } while ((c = read()) > ' ');
      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();
    }
  }


}
