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.*;
import java.util.stream.IntStream;

public class CodeForces{
	
	
	public static void main(String[] args) {
	  Scanner sc = new Scanner(System.in);
	  int a = sc.nextInt();
	  int b = sc.nextInt();
	  boolean t = true;
	  for(int i=2; i<b; i++) {
		  if(b%i==0) {
			  t=false;
			  break;
		  }
	  }
	  if(t) {
		  for(int w = a+1; w<b; w++) {
			  for(int p = 2; p<w; p++) {
				  if(w%p==0) {
					  break;
				  }
				  if(p==w-1) {
					  t=false;
				  }
			  }
		  }
	  }
	  if(t) {
		  System.out.println("YES");
	  }else {
		  System.out.println("NO");
	  }
	
	}
}
	  
    
  
 

