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 Task {
		
	public static void main(String[] args) throws IOException {
		new Task().solve();
	}
	
	PrintWriter out;
	int mul = 26+26+10;
	int nv = mul*mul+1;
	int[][] g;
	int[] pos;
	int cnt = 0;
	void solve() throws IOException{
		Reader in = new Reader("input.txt");
		out = new PrintWriter( new BufferedWriter(new OutputStreamWriter(System.out)) );
		//out = new PrintWriter(new FileWriter(new File("output.txt"))); 
		
		g = new int[nv][nv]; 
		
		int n = in.nextInt();
		
		for (int i = 0; i < n; i++) {
			String s = in.nextString();
			int v = h(s.charAt(0))*mul+h(s.charAt(1));
			int u = h(s.charAt(1))*mul+h(s.charAt(2));
			g[v][u]++;
		}
		
		int beg = -1;
		int fin = -1;
		int start = -1;
		
		for (int i = 0; i < nv; i++) {
			
			int inDeg = 0;
			int outDeg = 0;
			
			for (int j = 0; j < nv; j++) {
				
				if (g[i][j] > 0)
					outDeg+=g[i][j];
				
				if (g[j][i] > 0)
					inDeg+=g[j][i];
				
			}
			
			if (Math.abs(inDeg-outDeg) > 1) {
				System.out.print("NO");
				return;
			}
			
			if (inDeg + outDeg > 0) start = i;
			
			if (inDeg < outDeg) {
				if (beg == -1)
					beg = i;
				else {
					System.out.println("NO");
					return;
				}
			}
			
			if (inDeg > outDeg) {
				if (fin == -1)
					fin = i;
				else {
					System.out.println("NO");
					return;
				}
			}
			
		}
		
		if (beg == -1)
			beg = start;
		
		cnt = n+1;
		char[] res = new char[n+2];
		pos = new int[nv+1];
		eiler(beg, res);
		
		if (cnt > 0) {
			System.out.print("NO");
			return;
		}
		
		out.println("YES");
		for (int i = 0; i < n+2; i++) {
			out.print(res[i]);
		}
		
		out.flush();
		out.close();
	}
	
	int h(char ch) {
		
		int res = 0;
		
		if (ch >= 'a' && ch <= 'z')
			res = ch - 'a';
		else
		if (ch >= 'A' && ch <= 'Z')
			res = ch - 'A' + 26;
		else
			res = ch - '0' + 26*2;
		
		return res;
	}
	
	char dh(int n) {
		char res = ' ';
		
		if (n < 26)
			res = (char)(n+'a');
		else
		if (n < 52)
			res = (char) (n-26+'A');
		else
			res = (char) (n - 26*2 + '0');
		return res;
	}
	
	void eiler(int start, char[] res) {
		
		LinkedList<Integer> st = new LinkedList<>();
		
		st.push(start);
		
		while (!st.isEmpty()) {
			
			int p = st.peek();
			int u = -1;
			int i = pos[p];
			while ( i < nv && g[p][i] == 0 ) {
				i++;
			}
			
			if (i < nv) {
				pos[p] = i;
				g[p][i]--;
				st.push(i);
			}
			else {
				res[cnt] = dh(p%mul);
				cnt--;
				st.pop();
			}	
		}
		
		res[cnt] = dh(start/mul);
		cnt--;
		
	}

}
	
	
	
	class Reader {
	    
	    StringTokenizer token;
	    BufferedReader in;
	    
	    public Reader(String file) throws IOException {
	        //in = new BufferedReader( new FileReader( file ) );
	        in = new BufferedReader( new InputStreamReader( System.in ) );
	    }
	    
	    public byte nextByte() throws IOException {
	        return Byte.parseByte(Next());
	    }
	    
	    public int nextInt() throws IOException {
	        return Integer.parseInt(Next());
	    }
	    
	    public long nextLong() throws IOException {
	        return Long.parseLong(Next());
	    }
	    
	    public String nextString() throws IOException {
	        return in.readLine();
	    }
	    
	    private String Next() throws IOException {
	        while (token == null || !token.hasMoreTokens()) {
	            token = new StringTokenizer(in.readLine());
	        }
	        return token.nextToken();
	    }

	    
	}

	
