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.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;

public class NextPrime {
	public static void main(String[] args) throws IOException {
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		String[] temp = in.readLine().split(" ");
		int a = Integer.parseInt(temp[0]);
		int b = Integer.parseInt(temp[1]);
		boolean[] shieves = new boolean[b+1];
		Arrays.fill(shieves, true);
		shieves[0] = false;
		shieves[1] = false;
		for(int i  = 2;i*i<shieves.length;i++){
			if(shieves[i]){
				for(int j = i;i*j<shieves.length;j++){
					shieves[i*j] = false;
				}
			}
		}
		int getIndex = -1;
		for(int i = a+1;i<=b;i++) {
			if(shieves[i]) {
				getIndex = i;
				break;
			}
		}
		if(getIndex == b) {
			System.out.println("YES");
		} else {
			System.out.println("NO");
		}
	}
}
