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;

public class Main {


    public static void main(String[] args) {
       int n=50;
       Scanner in=new Scanner (System.in);
       //int a;

	boolean prime[]=new boolean[n+1];
	for (int i = 0; i <= n; ++i)
        {
            if(i%2==0){prime[i] = false;}
            else {prime[i]=true;}
        }
	prime[0] = prime[1] = false;
	prime[2]=true;

	for (int i = 3; i*i <= n; i+=2)
        {
	if (prime[i] == false)continue;
            for (int j = i*i; j <= n; j += i+i)
                {
                    prime[j] = false;
                }
	}
        int a=in.nextInt();
        int b=in.nextInt();
        int c=0;
        for(int i=a+1;i<n;i++)
        {
            if(prime[i]){c=i;break;}
        }
        if(c==b)System.out.println("YES");
        else System.out.println("NO");

    }
}