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.BufferedWriter;
import java.util.InputMismatchException;
import java.util.ArrayList;
import java.util.List;
import java.util.NoSuchElementException;
import java.math.BigInteger;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.Writer;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStreamWriter;
import java.util.Comparator;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 * @author Nguyen Trung Hieu - vuondenthanhcong11@gmail.com
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        OutputWriter out = new OutputWriter(outputStream);
        TaskD solver = new TaskD();
        solver.solve(1, in, out);
        out.close();
    }
}

class TaskD {
    private static final int MAXN = 40000;

    public void solve(int testNumber, InputReader in, OutputWriter out) {
        int count = in.readInt();
        String[] words = IOUtils.readStringArray(in, count);

        List<Integer>[] next = new List[MAXN];
        int[] exist = new int[MAXN];
        int[] begin = new int[MAXN];

        for (int i = 0; i < MAXN; i++) {
            next[i] = new ArrayList<Integer>();
        }

        for (String s : words) {
            int first = stringToHash(s.substring(0, 2));
            int second = stringToHash(s.substring(1, 3));
            next[first].add(second);
            exist[first]++;
            exist[second]--;
        }

        int hashStart = stringToHash(words[0].substring(0, 2));
        int hashEnd = stringToHash(words[0].substring(0, 2));
        int oddCount = 0;
        for (int i = 0; i < MAXN; i++) {
            if (exist[i] > 0) {
                if (exist[i] != 1) {
                    out.printLine("NO");
                    return;
                }
                hashStart = i;
                oddCount++;
            }

            if (exist[i] < 0) {
                if (exist[i] != -1) {
                    out.printLine("NO");
                    return;
                }
                hashEnd = i;
                oddCount++;
            }
        }

        if (oddCount != 0 && oddCount != 2) {
            out.printLine("NO");
            return;
        }

        List<Integer> answer = new ArrayList<Integer>();
        answer.add(hashStart);
        while (hashStart != hashEnd) {
            for (; begin[hashStart] < next[hashStart].size();) {
                int nextVal = next[hashStart].get(begin[hashStart]);
                begin[hashStart]++;
                hashStart = nextVal;
                break;
            }
            answer.add(hashStart);
        }

        for (int i = 0; i < answer.size(); i++) {
            int x = answer.get(i);
            int idx = i;
            while (next[x].size() != begin[x]) {
                int cur = x;
                do {
                    answer.add(idx, cur);
                    idx++;
                    for (; begin[cur] < next[cur].size();) {
                        int nextVal = next[cur].get(begin[cur]);
                        begin[cur]++;
                        cur = nextVal;
                        break;
                    }
                } while (cur != x);
            }
        }

        StringBuilder builder = new StringBuilder();
        for (int x : answer) {
            String s = hashToString(x);
            if (builder.length() == 0) {
                builder.append(s);
            } else {
                builder.append(s.charAt(1));
            }
        }

        if (builder.length() != count + 2) {
            out.printLine("NO");
            return;
        }

        out.printLine("YES");
        out.printLine(builder.toString());
    }

    private String hashToString(int x) {
        return "" + (char)(x >> 8) + (char)(x & ((1 << 8) - 1));
    }

    private Integer stringToHash(String s) {
        return (s.charAt(0) << 8) | s.charAt(1);
    }
}

class InputReader {
    private InputStream stream;
    private byte[] buf = new byte[1024];
    private int curChar;
    private int numChars;
    private SpaceCharFilter filter;

    public InputReader(InputStream stream) {
        this.stream = stream;
    }

    public int read() {
        if (numChars == -1)
            throw new InputMismatchException();
        if (curChar >= numChars) {
            curChar = 0;
            try {
                numChars = stream.read(buf);
            } catch (IOException e) {
                throw new InputMismatchException();
            }
            if (numChars <= 0)
                return -1;
        }
        return buf[curChar++];
    }

    public int readInt() {
        int c = read();
        while (isSpaceChar(c))
            c = read();
        int sgn = 1;
        if (c == '-') {
            sgn = -1;
            c = read();
        }
        int res = 0;
        do {
            if (c < '0' || c > '9')
                throw new InputMismatchException();
            res *= 10;
            res += c - '0';
            c = read();
        } while (!isSpaceChar(c));
        return res * sgn;
    }

    public boolean isSpaceChar(int c) {
        if (filter != null)
            return filter.isSpaceChar(c);
        return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    public String readString() {
        int c = read();
        while (isSpaceChar(c))
            c = read();
        StringBuffer res = new StringBuffer();
        do {
            res.appendCodePoint(c);
            c = read();
        } while (!isSpaceChar(c));
        return res.toString();
    }

    public interface SpaceCharFilter {
        public boolean isSpaceChar(int ch);
    }

}

class OutputWriter {
    private final PrintWriter writer;

    public OutputWriter(OutputStream outputStream) {
        writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    }

    public void print(Object...objects) {
        for (int i = 0; i < objects.length; i++) {
            if (i != 0)
                writer.print(' ');
            writer.print(objects[i]);
        }
    }

    public void printLine(Object...objects) {
        print(objects);
        writer.println();
    }

    public void close() {
        writer.close();
    }

}

class IOUtils {

    public static String[] readStringArray(InputReader in, int size) {
        String[] array = new String[size];
        for (int i = 0; i < size; i++)
            array[i] = in.readString();
        return array;
    }

}
