A prime number is a number which has exactly two distinct divisors: one and itself. For example, numbers 2, 7, 3 are prime, and 1, 6, 4 are not.

The next prime number after x is the smallest prime number greater than x. For example, the next prime number after 2 is 3, and the next prime number after 3 is 5. Note that there is exactly one next prime number after each number. So 5 is not the next prime number for 2.

One cold April morning Panoramix predicted that soon Kakofonix will break free from his straitjacket, and this will be a black day for the residents of the Gallic countryside.

Panoramix's prophecy tells that if some day Asterix and Obelix beat exactly x Roman soldiers, where x is a prime number, and next day they beat exactly y Roman soldiers, where y is the next prime number after x, then it's time to wait for Armageddon, for nothing can shut Kakofonix up while he sings his infernal song.

Yesterday the Gauls beat n Roman soldiers and it turned out that the number n was prime! Today their victims were a troop of m Romans (m > n). Determine whether the Gauls should wait for the black day after today's victory of Asterix and Obelix?

Input

The first and only input line contains two positive integers — n and m (2 ≤ n < m ≤ 50). It is guaranteed that n is prime.

Pretests contain all the cases with restrictions 2 ≤ n < m ≤ 4.

Output

Print YES, if m is the next prime number after n, or NO otherwise.

Examples

Input

3 5


Output

YES

Input

7 11


Output

YES

Input

7 9


Output

NO
import java.io.*;
import java.util.Arrays;

public class Panormix {
  
    public static void main(String[] args){
      
        try{
           
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            String[] temp = br.readLine().split(" ");
            int a = Integer.parseInt(temp[0]);
            int b = Integer.parseInt(temp[1]);
            boolean[] arr = new boolean[b+1];
            Arrays.fill(arr, true);
            arr[0] = false;
            arr[1] = false;

            for(int i = 2;i*i <=b; i++){
              if(arr[i]){
                for(int j = i; i*j <=b; j++){
                   arr[i*j] = false;
                }
              }
            }

            //System.out.println(Arrays.toString(arr));
            //System.out.println("The value of a is " + a + " and b is " + b+ " and the value of a+2 is "+ (a+2));
            int count = 0;
            if(arr[a] != true || arr[b] != true ){
              System.out.println("NO");
              return;
            }
            for(int i = a+1; i< b; i++){
               if(arr[i] == true){
                 count++;
               }
            }
            System.out.println((count > 0) ? "NO":"YES");
        
        }catch(IOException ioe){
          ioe.printStackTrace();
        }
    }
}
