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.Scanner;

public class Solution {
 
static boolean IsPrime(int m) {
		for(int i = 2;i<m;i++) {
			if(m%i == 0) {
				return false;
			}
		}
		return true;
	}
	
	static boolean IsNextPrime(int n, int m) {
		if(IsPrime(m) == false) {
			return false;
		}
        for(int i=n+1;i<52;i++) {
        	if(IsPrime(i) && i != m) {
        		return false;
        	}else if(IsPrime(i) && i == m) {
        		return true;
        	}
        }
        return true;
	}
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		int n = input.nextInt();
		int m = input.nextInt();
		boolean check = IsNextPrime(n,m);
		if(m%2 == 0 || m%n == 0 || check == false) {
			System.out.println("NO");
		}else {
			System.out.println("YES");
		} 
		 
    
    }
}
