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.util.*;
public class word{
        public static void main(String[] args){
            Scanner sc= new Scanner(System.in);
            int x=sc.nextInt();
            int k=sc.nextInt();
            for(int i=2; i<x; i++){
                    if(x%i==0){
                        System.out.print("NO");
                      System.exit(0);
                    }
            }
            int flag=0;
            for(int i=2;i<k;i++){
                if(k%i==0){
                System.out.print("NO");
                System.exit(0);}
            }

             if(x==0 || x==1 || k==0 || k==1){
                 System.out.print("NO");
                                 System.exit(0);}



            int j=x+1;
                for(int i=2;i<j;i++){
                    
                    if(j%i==0){
                        j++;
                        i=2;
                    }
                    

                }
            if(j==k){
                System.out.print("YES");
			System.exit(0);
            }
            else
                System.out.print("NO");

            }
            
            }
