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
//package Div2A;

import java.util.Scanner;

public class PanoramixPrediction {
	
	static int nextPrime(int n) {
		int c = 0;
		
		for (int i = n+1; i < 100; i++) {
			if(checkPrime(i)) {
				c = i;
				break;
			}
		}
		return c;
	}

	static boolean checkPrime(int n) {
		int sqrt = (int) Math.sqrt(n);
		boolean flag = true;
		
		if(n==1 || n==0) return false;

		if (n == 2 || n == 3 || n == 5 || n == 7 || n == 11)
			return true;

		for (int i = 2; i <= sqrt; i++) {
			if (n % i == 0) {
				flag = false;
				break;
			}
		}

		return flag;

	}

	public static void main(String[] args) {
		// TODO Auto-generated method stub

		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		int m = sc.nextInt();
		int key = nextPrime(n);
		
		System.out.println(m==key?"YES":"NO");
		

	}

}
