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.*;
public class pp {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner s=new Scanner (System.in);
		int a=s.nextInt();
		int b=s.nextInt();
		int flag=0;
		int cnt=a+1;
		int fg=0;
	while(flag!=1) {
		fg=0;
		if(Math.sqrt(cnt)<2) {
			if(b==3) {
				System.out.println("YES");
			}
			else {
				System.out.println("NO");
			}
			return;
		}
		int hu=(int)Math.sqrt(cnt);
		for(int i=2;i<=hu;i++) {
				if(cnt%i==0) {
					fg=1;
					break;
				}
				if((i==hu)&&(fg==0)) {
					if(cnt==b) {
						System.out.println("YES");
					}
					else {
						System.out.println("NO");
					}
					return;
				}
				//System.out.println("hiii"+cnt);
			}
		cnt++;
		}
	}

}
