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.util.*;

public class DMain {
    static class Link{
        final Node from;
        final Node to;

        Link(Node from, Node to) {
            this.from = from;
            this.to = to;
        }
    }
    static class Node {
        final String str;
        Stack<Link> inLinks = new Stack<Link>();
        Stack<Link> outLinks = new Stack<Link>();

        Node(String str) {
            this.str = str;
        }
    }

    static class Position {
        final Node node;

        Position next;

        Position(Node node) {
            this.node = node;
        }
    }

    Map<String, Node> nodes = new Hashtable<String, Node>();

    Node getNode(String str){
        Node node = nodes.get(str);
        if(null == node){
            node = new Node(str);
            nodes.put(str, node);
        }
        return node;
    }

    Link addLink(Node from, Node to){
        Link link = new Link(from, to);
        from.outLinks.add(link);
        to.inLinks.add(link);
        return link;
    }

    Position createFromPosition(Position start){
        Node node = start.node;
        Position curr = start;
        while(node.outLinks.size() > 0) {
            Link link = node.outLinks.pop();
            node = link.to;
            Position nextPos = new Position(node);
            curr.next = nextPos;
            curr = nextPos;
        }
        return curr;
    }

    public void solve() {
        Parser parser = new Parser();

        int n = parser.nextInteger();
        parser.nextLine();
        HashSet<String> keys = new HashSet<String>();

        for(int i = 0; i < n; ++i){
            String str = parser.nextLine();
            Node from = getNode(str.substring(0, 2));
            Node to = getNode(str.substring(1, 3));
            addLink(from, to);
        }

        Node start = null;
        for(Node node : nodes.values()){
            if(node.inLinks.size() == node.outLinks.size()) continue;
            if(Math.abs(node.inLinks.size() - node.outLinks.size()) > 1){
                System.out.print("NO");
                return;
            }
            if(node.inLinks.size() < node.outLinks.size()){
                if(start != null){
                    System.out.print("NO");
                    return;
                }
                start = node;
            }
        }
        if(null == start){
            start = nodes.values().iterator().next();
        }

        Position first = new Position(start);
        createFromPosition(first);
        for(Position now = first; now != null; now = now.next){
            if(now.node.outLinks.size() == 0)continue;
            Position next = now.next;
            Position last = createFromPosition(now);
            if(last.node != now.node){
                System.out.print("NO");
                return;
            }
            last.next = next;
        }

        Position now = first;
        StringBuilder builder = new StringBuilder();
        builder.append(now.node.str);
        now = now.next;
        while(now != null){
            builder.append(now.node.str.substring(1, 2));
            now = now.next;
        }
        if(builder.length() < n + 2) {
            System.out.print("NO");
            return;
        }
        System.out.print("YES");
        System.out.println();
        System.out.print(builder.toString());
    }

    public static void main(String[] args) {
        new DMain().solve();
    }

    static public class Parser{
        Scanner scanner;

        public Parser() {
            scanner = new Scanner(System.in);
        }

        public Parser(String str) {
            scanner = new Scanner(str);
        }

        long nextLong(){
            return scanner.nextLong();
        }

        int nextInteger(){
            return scanner.nextInt();
        }

        double nextDouble(){
            return scanner.nextDouble();
        }

        String nextLine(){
            return scanner.nextLine();
        }

        int[] nextIntegers(int count){
            int[] result = new int[count];
            for(int i = 0; i < count; ++i){
                result[i] = nextInteger();
            }
            return result;
        }

        long[] nextLongs(int count){
            long[] result = new long[count];
            for(int i = 0; i < count; ++i){
                result[i] = nextLong();
            }
            return result;
        }

        int[][] nextIntegers(int fields, int count){
            int[][] result = new int[fields][];
            for(int i = 0; i < fields; ++i){
                result[i] = new int[count];
            }
            for(int c = 0; c < count; ++c){
                for(int i = 0; i < fields; ++i){
                    result[i][c] = nextInteger();
                }
            }
            return result;
        }
    }

    static public class Matrix{
        static public final int size = 101;
        static public final long base = 1000000007;

        static public class Vector{
            long[] data = new long[size];
        }
        private long[] data;

        public Matrix() {
            data = new long[size * size];
        }

        long get(int row, int column){
            return data[row * size + column];
        }

        long set(int row, int column, long value){
            int index = row * size + column;
            long result = data[index];
            data[index] = value;
            return result;
        }

        public Matrix mul(Matrix other){
            Matrix result = new Matrix();
            for(int r = 0; r < size; ++r){
                for(int c = 0; c < size; ++c){
                    long value = 0;
                    for(int i = 0; i < size; ++i){
                        value += get(r, i) * other.get(i, c);
                        value %= base;
                    }
                    result.set(r, c, value);
                }
            }
            return result;
        }




    }
}
