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 D implements Runnable{
	public static void main (String[] args) {new Thread(null, new D(), "_cf", 1 << 28).start();}

	int[] ptr;
	ArrayList<Integer> list, adj[];
	
	public void run() {
		FastScanner fs = new FastScanner();
		PrintWriter out = new PrintWriter(System.out);
		System.err.println("Go!");

		int max = 62*62;
		HashMap<String, Integer> map = new HashMap<>();
		HashMap<Integer, String> rap = new HashMap<>();
		adj = new ArrayList[max];
		for(int i = 0; i < adj.length; i++)
			adj[i] = new ArrayList<>();
		int[] inDeg = new int[max];
		int[] otDeg = new int[max];
		int n = fs.nextInt(), on = n;
		for(int i = 0; i < n; i++) {
			String x = fs.next();
			String one = x.charAt(0)+""+x.charAt(1);
			String two = x.charAt(1)+""+x.charAt(2);
			if(!map.containsKey(one)) {
				map.put(one, map.size());
				rap.put(map.size()-1, one);
			}
			if(!map.containsKey(two)) {
				map.put(two, map.size());
				rap.put(map.size()-1, two);
			}
			adj[map.get(one)].add(map.get(two));
			inDeg[map.get(two)]++;
			otDeg[map.get(one)]++;
		}
		adj = Arrays.copyOfRange(adj, 0, map.size());
		n = map.size();
		int su = -1, eu = -1;
		for(int i = 0; i < n; i++) {
			if(inDeg[i] > otDeg[i]) {
				if(eu != -1 || inDeg[i]-otDeg[i] > 1) {
					System.out.println("NO");
					return;
				}
				eu = i;
			}
			else if(inDeg[i] < otDeg[i]) {
				if(su != -1 || otDeg[i]-inDeg[i] > 1) {
					System.out.println("NO");
					return;
				}
				su = i;
			}
		}
		if(su == -1) su = 0;
		ptr = new int[n];
		list = new ArrayList<>();
		
		//Hierholzer�s Algorithm
		dfs(su);
		StringBuilder res = new StringBuilder();
		for(int i = list.size()-1; i >= 0; i--) {
			String x = rap.get(list.get(i));
			if(res.length() == 0) res.append(x);
			else res.append(x.charAt(x.length()-1));
		}
		if(res.length() != on+2) {
			out.println("NO");
		}
		else {
			out.println("YES");
			out.println(res);
		}

		out.close();
	}
	
	void dfs(int u) {
		while(ptr[u] < adj[u].size()) {
			int v = adj[u].get(ptr[u]++);
			dfs(v);
		}
		list.add(u);
	}

	class FastScanner {
		public int BS = 1<<16;
		public char NC = (char)0;
		byte[] buf = new byte[BS];
		int bId = 0, size = 0;
		char c = NC;
		double num = 1;
		BufferedInputStream in;

		public FastScanner() {
			in = new BufferedInputStream(System.in, BS);
		}

		public FastScanner(String s) throws FileNotFoundException {
			in = new BufferedInputStream(new FileInputStream(new File(s)), BS);
		}

		public char nextChar(){
			while(bId==size) {
				try {
					size = in.read(buf);
				}catch(Exception e) {
					return NC;
				}                
				if(size==-1)return NC;
				bId=0;
			}
			return (char)buf[bId++];
		}

		public int nextInt() {
			return (int)nextLong();
		}

		public long nextLong() {
			num=1;
			boolean neg = false;
			if(c==NC)c=nextChar();
			for(;(c<'0' || c>'9'); c = nextChar()) {
				if(c=='-')neg=true;
			}
			long res = 0;
			for(; c>='0' && c <='9'; c=nextChar()) {
				res = (res<<3)+(res<<1)+c-'0';
				num*=10;
			}
			return neg?-res:res;
		}

		public double nextDouble() {
			double cur = nextLong();
			return c!='.' ? cur:cur+nextLong()/num;
		}

		public String next() {
			StringBuilder res = new StringBuilder();
			while(c<=32)c=nextChar();
			while(c>32) {
				res.append(c);
				c=nextChar();
			}
			return res.toString();
		}

		public String nextLine() {
			StringBuilder res = new StringBuilder();
			while(c<=32)c=nextChar();
			while(c!='\n') {
				res.append(c);
				c=nextChar();
			}
			return res.toString();
		}

		public boolean hasNext() {
			if(c>32)return true;
			while(true) {
				c=nextChar();
				if(c==NC)return false;
				else if(c>32)return true;
			}
		}
		
		public int[] nextIntArray(int n) {
			int[] res = new int[n];
			for(int i = 0; i < n; i++) res[i] = nextInt();
			return res;
		}
		
	}

}