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
// Marcelino Galarza
// September 9th, 2018

import java.util.Arrays;
import java.util.Scanner;
public class PanoramixsPrediction {

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int num = in.nextInt();
		int next = in.nextInt();
		
		boolean[] primes = primeSieve(50);
		
		int answer = 0;
		for (int i = num+1; i <= 50; i++) {
			if (primes[i]) {
				answer = i;
				break;
			}
		}
		
		if (next == answer)
			System.out.println("YES");
		else
			System.out.println("NO");
	}

	public static boolean[] primeSieve(int num) {
		boolean[] prime = new boolean[num+1];
		Arrays.fill(prime, true);
		
		for (int i = 2; i*i <= num; i++)
			if (prime[i])
				for (int j = i*2; j <= num; j += i)
					prime[j] = false;
		
		return prime;
	}
}
