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 prediction
{
    public static void main(String args[])
    {
        Scanner in=new Scanner(System.in);
        long n,m,a,i;
        boolean b=false;
        boolean bool=true;
        n=in.nextLong();
        m=in.nextLong();
        long num=n+1;
        for(a=2;a<m;a++)
        {
            if(m%a==0)
            {
                b=true;
            }
        }
        if(b==true)
        {
            System.out.println("NO");
            System.exit(0);
        }
        else if(m-n==1)
        {
            System.out.println("YES");
            System.exit(0);
        }
        else
        {
            while(num!=m)
            {
                bool=true;
                for(i=2;i<num;i++)
                {
                    if(num%i==0)
                    {
                        bool=false;
                    }
                }
                if(bool==true)
                {
                    System.out.println("NO");
                    System.exit(0);
                }
                num++;
            }
            System.out.println("YES");
        }
    }
}

                        
            