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;
import java.io.IOException;
import java.lang.Math;
import java.util.Arrays;

public class sol {
	public static void main(String args[]) throws IOException {
		Scanner in = new Scanner(System.in);
		int n = in.nextInt();
		int m = in.nextInt();

		boolean isprime[] = new boolean[51];
		Arrays.fill(isprime, true);
		isprime[0] = isprime[1] = false;
		double bound = Math.sqrt(50);
		
		int ind = 4;
		while (ind <= 50) {
			isprime[ind] = false;
			ind += 2;
		}

		for (int i = 3; i <= bound; i += 2) {
			if (isprime[i] == true) {
				ind = i*3;
				while (ind <= 50) {
					isprime[ind] = false;
					ind += i*2;
				}
			}
		}

		boolean foundp = false;

		for (int i = n + 1; i < m; i++) {
			if (isprime[i] == true) {
				System.out.println("NO");
				foundp = true;
				break;
			}
		}

		if (foundp == false) {
			if (isprime[m] == true) System.out.println("YES");
			else System.out.println("NO");
		}
	}
}