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;

public class Panoramix_prediction {


    static boolean isPrime(long num)
    {
        if(num<2)
        {
            return false;
        }

        for(int i=2; i<num; i++)
        {
            if(num%i==0)
            {
                return false;
            }
        }
        return true;
    }


    static void solve(String[] arr)
    {
        long start = Long.parseLong(arr[0])+1;
        long check = Long.parseLong(arr[1]);
        boolean flag=false;

        while(true)
        {
            if(isPrime(start))
            {
                if(start == check)
                {
                    flag=true;
                    break;
                }
                else
                {
                    break;
                }
            }
            start++;
        }

        if(!flag)
        {
            System.out.println("NO");
        }
        else
        {
            System.out.println("YES");
        }

    }


    public static void main(String[] args) throws IOException
    {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        String[] arr = br.readLine().split(" ");

        solve(arr);

    }
}
