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.Arrays;
import java.util.HashMap;
import java.util.Scanner;
import java.util.Vector;

public class Ended {

	static int n;
	static int m;

	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		int n = input.nextInt();
		int m = input.nextInt();
		for (int i = n + 1; i < n + 7; i++) {
			boolean composite = false;
			int j;
			for (j = 2; j <= 9; j++) {
				if (i != j && i % j == 0) {					
					composite = true;
					break;
				}
			}
			if (!composite) {
				if (i == m) {
					System.out.println("YES");
					return;
				} else {
					System.out.println("NO");
					return;
				}
			}
		}
	}

	static class State {
		int stt;
		String num;

		public State(int x, String num1) {
			stt = x;
			num = num1;
		}
	}
}