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 A80_Panoramixs_Prediction {
	
	
	static boolean isPrime (int x) { 
		if (x==2 || x==3 || x==5 || x== 7 )return true ; 
		for (int i =2 ; i<=Math.sqrt(x)+1 ; ++i) { 
			if (x%i==0)
				return false ; 
		}
		return true ; 
	}
	public static void main(String[] args) {
		Scanner ss =new Scanner (System.in) ; 
		int n = ss.nextInt() ; 
		int m = ss.nextInt() ; 
		for (int i = n+1;i<m ; ++i ) { 
			if (isPrime(i))
			{
				System.out.println("NO");
				return ; 
			}
		}
		if (isPrime(m)) {
			System.out.println("YES");
		}
		else {
			System.out.println("NO");
		}
	}

}
