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.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Calendar;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.PriorityQueue;
import java.util.SortedSet;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.TreeMap;
import java.util.TreeSet;

/**
 * #
 * @author pttrung
 */
public class D_Round_288_Div2 {

    public static long MOD = 1000000007;

    public static void main(String[] args) throws FileNotFoundException {
        // PrintWriter out = new PrintWriter(new FileOutputStream(new File(
        // "output.txt")));
        PrintWriter out = new PrintWriter(System.out);
        Scanner in = new Scanner();
        int n = in.nextInt();
        String[] data = new String[n];
        HashMap<String, ArrayList<String>> map = new HashMap();
        final HashMap<String, Integer> countIn = new HashMap();
        final HashMap<String, Integer> countOut = new HashMap();
        HashMap<String, Integer> sub = new HashMap();
        for (int i = 0; i < n; i++) {
            data[i] = in.next();
            String a = data[i].substring(0, 2);
            String b = data[i].substring(1);
            if (!sub.containsKey(a)) {
                sub.put(a, 0);
            } else {
                sub.put(a, sub.get(a) + 1);
            }
            if (!sub.containsKey(b)) {
                sub.put(b, 0);
            } else {

                sub.put(b, sub.get(b) + 1);
            }
            if (!map.containsKey(a)) {
                map.put(a, new ArrayList());
            }
            map.get(a).add(b);
            if (!countIn.containsKey(b)) {
                countIn.put(b, 0);
            }
            if (!countOut.containsKey(a)) {
                countOut.put(a, 0);
            }
            countIn.put(b, countIn.get(b) + 1);
            countOut.put(a, countOut.get(a) + 1);
        }
        boolean ok = true;
        String start = null;
        int c = 0;
        for (String v : sub.keySet()) {
            int x = countIn.containsKey(v) ? countIn.get(v) : 0;
            int y = countOut.containsKey(v) ? countOut.get(v) : 0;
            if (y > 0 && start == null) {
                start = v;
            }
            if (x != y) {
                c++;
                if (Math.abs(x - y) != 1) {
                    ok = false;
                    break;
                }
                if (x + 1 == y) {
                    start = v;
                }
            }
        }
        //System.out.println(c);
        ok &= (c == 0 || c == 2);
        if (ok) {

            // System.out.println(start);
            StringBuilder result = new StringBuilder();
            HashMap<String, Integer> count = new HashMap();
            Stack<String> forward = new Stack();
            Stack<String> backward = new Stack();
            //backward.add(start);
            for (String v : map.keySet()) {
                count.put(v, 0);
            }
            //System.out.println(start);

            while (true) {
                if (map.containsKey(start)
                        && map.get(start).size() > count.get(start)) {
                    String tmp = map.get(start).get(count.get(start));
                    count.put(start, count.get(start) + 1);
                    forward.push(start.charAt(0) + tmp);
                    start = tmp;
                } else {
                    break;
                }
            }
            while (!forward.isEmpty()) {
                start = forward.pop();
                backward.push(start);
                start = start.substring(0, 2);
                while (true) {
                    if (map.containsKey(start)
                            && map.get(start).size() > count.get(start)) {
                        String tmp = map.get(start).get(count.get(start));
                        count.put(start, count.get(start) + 1);
                        forward.push(start.charAt(0) + tmp);
                        start = tmp;
                    } else {
                        break;
                    }
                }
            }
            result.append(backward.pop());
            while (!backward.isEmpty()) {
                String v = backward.pop();
                result.append(v.charAt(2));

            }
            if (result.length() == n + 2) {
                out.println("YES");
                out.println(result);
            } else {
                out.println("NO");
            }
        } else {
            out.println("NO");
        }

        out.close();
    }

    public static int[] KMP(String val) {
        int i = 0;
        int j = -1;
        int[] result = new int[val.length() + 1];
        result[0] = -1;
        while (i < val.length()) {
            while (j >= 0 && val.charAt(j) != val.charAt(i)) {
                j = result[j];
            }
            j++;
            i++;
            result[i] = j;
        }
        return result;

    }

    public static boolean nextPer(int[] data) {
        int i = data.length - 1;
        while (i > 0 && data[i] < data[i - 1]) {
            i--;
        }
        if (i == 0) {
            return false;
        }
        int j = data.length - 1;
        while (data[j] < data[i - 1]) {
            j--;
        }
        int temp = data[i - 1];
        data[i - 1] = data[j];
        data[j] = temp;
        Arrays.sort(data, i, data.length);
        return true;
    }

    public static int digit(long n) {
        int result = 0;
        while (n > 0) {
            n /= 10;
            result++;
        }
        return result;
    }

    public static double dist(long a, long b, long x, long y) {
        double val = (b - a) * (b - a) + (x - y) * (x - y);
        val = Math.sqrt(val);
        double other = x * x + a * a;
        other = Math.sqrt(other);
        return val + other;



    }

    public static class Point implements Comparable<Point> {

        int x, y;

        public Point(int start, int end) {
            this.x = start;
            this.y = end;
        }

        @Override
        public int hashCode() {
            int hash = 5;
            hash = 47 * hash + this.x;
            hash = 47 * hash + this.y;
            return hash;
        }

        @Override
        public boolean equals(Object obj) {
            if (obj == null) {
                return false;
            }
            if (getClass() != obj.getClass()) {
                return false;
            }
            final Point other = (Point) obj;
            if (this.x != other.x) {
                return false;
            }
            if (this.y != other.y) {
                return false;
            }
            return true;
        }

        @Override
        public int compareTo(Point o) {
            return x - o.x;
        }
    }

    public static class FT {

        long[] data;

        FT(int n) {
            data = new long[n];
        }

        public void update(int index, long value) {
            while (index < data.length) {
                data[index] += value;
                index += (index & (-index));
            }
        }

        public long get(int index) {
            long result = 0;
            while (index > 0) {
                result += data[index];
                index -= (index & (-index));
            }
            return result;

        }
    }

    public static long gcd(long a, long b) {
        if (b == 0) {
            return a;
        }
        return gcd(b, a % b);
    }

    public static long pow(long a, long b, long MOD) {
        if (b == 0) {
            return 1;
        }
        if (b == 1) {
            return a;
        }
        long val = pow(a, b / 2, MOD);
        if (b % 2 == 0) {
            return val * val % MOD;
        } else {
            return val * (val * a % MOD) % MOD;


        }
    }

    static class Scanner {

        BufferedReader br;
        StringTokenizer st;

        public Scanner() throws FileNotFoundException {
            // System.setOut(new PrintStream(new BufferedOutputStream(System.out), true));
            br = new BufferedReader(new InputStreamReader(System.in));
            //  br = new BufferedReader(new InputStreamReader(new FileInputStream(new File("input.txt"))));
        }

        public String next() {

            while (st == null || !st.hasMoreTokens()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    throw new RuntimeException();
                }
            }
            return st.nextToken();
        }

        public long nextLong() {
            return Long.parseLong(next());
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public double nextDouble() {
            return Double.parseDouble(next());
        }

        public String nextLine() {
            st = null;
            try {
                return br.readLine();
            } catch (Exception e) {
                throw new RuntimeException();
            }
        }

        public boolean endLine() {
            try {
                String next = br.readLine();
                while (next != null && next.trim().isEmpty()) {
                    next = br.readLine();
                }
                if (next == null) {
                    return true;
                }
                st = new StringTokenizer(next);
                return st.hasMoreTokens();
            } catch (Exception e) {
                throw new RuntimeException();
            }
        }
    }
}
