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 java.util.*;


import java.io.*;
import java.math.*;
public class A
	
	{ 
		 static FastReader sc=new FastReader(); 
		 
			  public static void main(String[] args)
	    {
				    //CHECK FOR N=1
	       	//CHECK FOR N=1
		    //CHECK FOR N=1
	       	//CHECK FOR N=1
		  
		  PrintWriter out=new PrintWriter(System.out);
		  StringBuffer sb=new StringBuffer("");
	  int ttt=1;
	   //  ttt =i(); 
	 
        outer :while (ttt-- > 0) 
		{
        	char A[]=s().toCharArray();
        	char B[]=s().toCharArray();
        	int n=A.length;
        	int ind=-1;
        	for(int i=0;i<n;i++) {
        		if(A[i]<B[i]) {
        			if(B[i]-A[i]>1) {
        				A[i]++;
        				ind=1;
        				break;
        			}
        		}
        	}
        	if(ind==1) {
        		for(char ch : A) {
        			out.print(ch);
        		}
        		out.flush();
        		return;
        	}
        	
        	
        	for(int i=0;i<n;i++) {
        		if(A[i]<B[i]) {
        			ind=i;
        			break;
        		}
        	}
        	int a=0,b=0;
        	for(int i=ind+1;i<n;i++) {
        		if(A[i]=='z')
        			a++;
        		if(B[i]=='a')
        			b++;
        	}
        	int len=n-ind-1;
        	if(a==len && b==len) {
        		System.out.println("No such string");
        		return;
        	}
        	if(a==len) {
        		for(int i=ind+1;i<n;i++) {
        			if(B[i]!='a') {
        				B[i]--;
        			}
        		}
        		for(char ch : B) {
        			out.print(ch);
        		}
        	}
        	else {
        		for(int i=ind+1;i<n;i++) {
        			if(A[i]!='z') {
        				A[i]++;
        			}
        		}
        		for(char ch : A) {
        			out.print(ch);
        		}
        	}
        	
        	
        	
        	
		}
	   out.close();
      // System.out.println(sb.toString());
       
       
       //CHECK FOR N=1                    //CHECK FOR M=0
        //CHECK FOR N=1                    //CHECK FOR M=0
       	//CHECK FOR N=1
       	//CHECK FOR N=1
       	//CHECK FOR N=1
    }
	


static int[] input(int n) {
  	int A[]=new int[n];
  	   for(int i=0;i<n;i++) {
  		   A[i]=sc.nextInt();
  	   }
  	   return A;
     }
  static long[] inputL(int n) {
  	long A[]=new long[n];
  	   for(int i=0;i<n;i++) {
  		   A[i]=sc.nextLong();
  	   }
  	   return A;
     }
  static String[] inputS(int n) {
  	String A[]=new String[n];
  	   for(int i=0;i<n;i++) {
  		   A[i]=sc.next();
  	   }
  	   return A;
     }
  static long sum(int A[]) {
  	long sum=0;
  	for(int i : A) {
  		sum+=i;
  	}
  	return sum;
  }
  static long sum(long A[]) {
  	long sum=0;
  	for(long i : A) {
  		sum+=i;
  	}
  	return sum;
  }

  static void input(int A[],int B[]) {
  	   for(int i=0;i<A.length;i++) {
  		   A[i]=sc.nextInt();
  		   B[i]=sc.nextInt();
  	   }
  }
  static int[][] input(int n,int m){
  	int A[][]=new int[n][m];
  	for(int i=0;i<n;i++) {
  		for(int j=0;j<m;j++) {
  			A[i][j]=i();
  		}
  	}
  	return A;
  }
  static char[][] charinput(int n,int m){
  	char A[][]=new char[n][m];
  	for(int i=0;i<n;i++) {
  		String s=s();
  		for(int j=0;j<m;j++) {
  			A[i][j]=s.charAt(j);
  		}
  	}
  	return A;
  }
  static int max(int A[]) {
  	int max=Integer.MIN_VALUE;
  	for(int i=0;i<A.length;i++) {
  		max=Math.max(max, A[i]);
  	}
  	return max;
  }
  static int min(int A[]) {
  	int min=Integer.MAX_VALUE;
  	for(int i=0;i<A.length;i++) {
  		min=Math.min(min, A[i]);
  	}
  	return min;
  }
  static long max(long A[]) {
  	long max=Long.MIN_VALUE;
  	for(int i=0;i<A.length;i++) {
  		max=Math.max(max, A[i]);
  	}
  	return max;
  }
  static long min(long A[]) {
  	long min=Long.MAX_VALUE;
  	for(int i=0;i<A.length;i++) {
  		min=Math.min(min, A[i]);
  	}
  	return min;
  }
  static long mod(long x) {
  	 int mod=1000000007;
  	  return ((x%mod + mod)%mod);
  }
  static String reverse(String s) {
  	StringBuffer p=new StringBuffer(s);
  	p.reverse();
  	return p.toString();
  }

       static int i() {
      	 return sc.nextInt();
       }
       static String s() {
      	 return sc.next();
       }
       static long l() {
      	 return sc.nextLong();
       }  
       static void sort(int[] A){
          int n = A.length;
          Random rnd = new Random();
          for(int i=0; i<n; ++i){
              int tmp = A[i];
              int randomPos = i + rnd.nextInt(n-i);
              A[i] = A[randomPos];
              A[randomPos] = tmp;
          }
          Arrays.sort(A);
       }
       static void sort(long[] A){
  	        int n = A.length;
  	        Random rnd = new Random();
  	        for(int i=0; i<n; ++i){
  	            long tmp = A[i];
  	            int randomPos = i + rnd.nextInt(n-i);
  	            A[i] = A[randomPos];
  	            A[randomPos] = tmp;
  	        }
  	        Arrays.sort(A);
  	     }
    static String sort(String s) {
   	 Character ch[]=new Character[s.length()];
   	 for(int i=0;i<s.length();i++) {
   		 ch[i]=s.charAt(i);
   	 }
   	 Arrays.sort(ch);
   	 StringBuffer st=new StringBuffer("");
 for(int i=0;i<s.length();i++) {
	 st.append(ch[i]);
 }
 return st.toString();
}
static HashMap<Integer,Integer> hash(int A[]){
  HashMap<Integer,Integer> map=new HashMap<Integer, Integer>();
  for(int i : A) {
	  if(map.containsKey(i)) {
		  map.put(i, map.get(i)+1);
	  }
	  else {
		  map.put(i, 1);
	  }
  }
  return map;
}
static HashMap<Long,Integer> hash(long A[]){
	  HashMap<Long,Integer> map=new HashMap<Long, Integer>();
	  for(long i : A) {
		  if(map.containsKey(i)) {
			  map.put(i, map.get(i)+1);
		  }
		  else {
			  map.put(i, 1);
		  }
	  }
	  return map;
	}
static TreeMap<Integer,Integer> tree(int A[]){
  TreeMap<Integer,Integer> map=new TreeMap<Integer, Integer>();
  for(int i : A) {
	  if(map.containsKey(i)) {
		  map.put(i, map.get(i)+1);
	  }
	  else {
		  map.put(i, 1);
	  }
  }
  return map;
}
static TreeMap<Long,Integer> tree(long A[]){
	  TreeMap<Long,Integer> map=new TreeMap<Long, Integer>();
	  for(long i : A) {
		  if(map.containsKey(i)) {
			  map.put(i, map.get(i)+1);
		  }
		  else {
			  map.put(i, 1);
		  }
	  }
	  return map;
	}
   static boolean prime(int n) 
    { 
        if (n <= 1) 
            return false; 
        if (n <= 3) 
            return true; 
        if (n % 2 == 0 || n % 3 == 0) 
            return false; 
        double sq=Math.sqrt(n);
  
        for (int i = 5; i <= sq; i = i + 6) 
            if (n % i == 0 || n % (i + 2) == 0) 
                return false; 
        return true; 
    } 
   static boolean prime(long n) 
    { 
        if (n <= 1) 
            return false; 
        if (n <= 3) 
            return true; 
        if (n % 2 == 0 || n % 3 == 0) 
            return false; 
        double sq=Math.sqrt(n);
  
        for (int i = 5; i <= sq; i = i + 6) 
            if (n % i == 0 || n % (i + 2) == 0) 
                return false; 
        return true; 
    } 
   static int gcd(int a, int b) 
   { 
       if (a == 0) 
           return b; 
       return gcd(b % a, a); 
   } 
   static long gcd(long a, long b) 
   { 
       if (a == 0) 
           return b; 
       return gcd(b % a, a); 
   } 
   static class Pair implements Comparable<Pair>
   {
  	 int x;
  	 int y;
  	 Pair(int x,int y){
  		 this.x=x;
  		 this.y=y;
  	 }
	@Override
	public int compareTo(Pair o) {
		if(this.x>o.x)
			return 1;
		else if(this.x<o.x)
			return -1;
		else {
			if(this.y<o.y)
				return 1;
			else if(this.y>o.y)
				return -1;
			else
				return 0;
		}
	}
   }
      
  static class FastReader 
  { 
      BufferedReader br; 
      StringTokenizer st; 

      public FastReader() 
      { 
          br = new BufferedReader(new
                   InputStreamReader(System.in)); 
      } 

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

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

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

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

      String nextLine() 
      { 
          String str = ""; 
              try
              { 
                  str = br.readLine(); 
              } 
              catch (IOException e) 
              { 
                  e.printStackTrace(); 
              } 
              return str; 
          } 
      } 
  } 



