Vitaly is a diligent student who never missed a lesson in his five years of studying in the university. He always does his homework on time and passes his exams in time. 

During the last lesson the teacher has provided two strings s and t to Vitaly. The strings have the same length, they consist of lowercase English letters, string s is lexicographically smaller than string t. Vitaly wondered if there is such string that is lexicographically larger than string s and at the same is lexicographically smaller than string t. This string should also consist of lowercase English letters and have the length equal to the lengths of strings s and t. 

Let's help Vitaly solve this easy problem!

Input

The first line contains string s (1 ≤ |s| ≤ 100), consisting of lowercase English letters. Here, |s| denotes the length of the string.

The second line contains string t (|t| = |s|), consisting of lowercase English letters.

It is guaranteed that the lengths of strings s and t are the same and string s is lexicographically less than string t.

Output

If the string that meets the given requirements doesn't exist, print a single string "No such string" (without the quotes).

If such string exists, print it. If there are multiple valid strings, you may print any of them.

Examples

Input

a
c


Output

b


Input

aaa
zzz


Output

kkk


Input

abcdefg
abcdefh


Output

No such string

Note

String s = s1s2... sn is said to be lexicographically smaller than t = t1t2... tn, if there exists such i, that s1 = t1, s2 = t2, ... si - 1 = ti - 1, si < ti.
import javax.swing.text.Segment;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.StringTokenizer;

public class Main {

    public static class FastScanner {
        BufferedReader br;
        StringTokenizer st;
        FastScanner() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }
        String nextLine() {
            String res = "";
            try {
                res = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return res;
        }

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

        int nextInt() {
            return Integer.parseInt(next());
        }
        long nextLong() {return Long.parseLong(next());}
        double nextDouble () {return Double.parseDouble(next());}
        float nextFloat() {return Float.parseFloat(next());}
        byte nextByte() {return Byte.parseByte(next());}
        short nextShort() {return Short.parseShort(next());}
    }

    static FastScanner scanner = new FastScanner();

    static public List<Integer> range(int l, final int r) {
        List<Integer> res = new ArrayList<>();
        for (; l < r; ++l)
            res.add(l);
        return res;
    };

    static public List<Integer> range(int l, final int r, final int step) {
        List<Integer> res = new ArrayList<>();
        if (step > 0) {
            for (; l < r; l += step)
                res.add(l);
        } else if (step < 0) {
            for (; l > r; l += step)
                res.add(l);
        }
        return res;
    };

    static public List<Integer> range(final int x) {
        List<Integer> res = new ArrayList<>();
        for (int i = 0; i < x; ++i)
            res.add(i);
        return res;
    };

    public static void main(String[] args) {
        final String s = scanner.nextLine(), t = scanner.nextLine();
        final int n = s.length();
        char[] res = new char[n];
        int rem = 1;
        for (final int i : range(n))
            res[i] = s.charAt(i);
        for (final int i : range(n - 1, -1, -1)) {
            if (rem == 0)
                break;
            if (res[i] == 'z') {
                rem = 1;
                res[i] = 'a';
            } else {
                res[i] = (char)(res[i] + 1);
                rem = 0;
            }
        }
        for (final int i : range(n)) {
            if (res[i] < t.charAt(i)) {
                for (final int j : range(n))
                    System.out.print(res[j]);
                System.out.println();
                return;
            }
            if (res[i] > t.charAt(i)) {
                System.out.println("No such string");
                return;
            }
        }
        System.out.println("No such string");
    }
}
