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 PanoPredict
{
    public static void main(String[] args) 
    {
        // Set up scanner
        Scanner sc = new Scanner(System.in); 
        // System.out.println("Enter n");
        int n = sc.nextInt();
        // System.out.println("Enter m");
        int m  = sc.nextInt();
        
        boolean[] a = primesieve(100);
        int start = n+1;
        while (a[start] == true)
        {
            start++;
        }
        if (start == m)
        {
            System.out.println("YES");
        }
        else
        {
            System.out.println("NO");
        }
    }
       
    // WARNING:  For efficiency purposes, true means is it NOT prime, false means prime
    private static boolean[] primesieve(int size)
    {
        // True will mean it is NOT prime
        boolean[] returnme = new boolean[size];  // Default in Java to all false
        returnme[0] = true;
        returnme[1] = true;
        int nextfalse = 2;
        while (nextfalse < Math.sqrt(size) + 1)
        {
            for (int i = nextfalse * nextfalse; i < size; i+=nextfalse)
            {
                returnme[i] = true;
            }
            nextfalse++;
            while (returnme[nextfalse] == true)
            {
                nextfalse++;
            }
        }
        return returnme;
    }
}