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.PrintWriter;
import java.util.Arrays;
import java.util.Scanner;


public class Main {
    private static int arr2[] = new int[51],b;
    private static Scanner input = new Scanner(System.in);
    public static void main(String[] args) throws Exception {
        PrintWriter out = new PrintWriter(System.out);
        boolean arr[] = new boolean[51];
        
        Arrays.fill(arr, true);
        arr[0] = arr[1] = false;
        for(int i=2;i*i<51;++i)
            if(arr[i])
                for(int j=i*i;j<51;j+=i)
                    arr[j]=false;
        
        b=-1;
        for(int i=0;i<51;++i)
            if(arr[i])
                arr2[++b]=i;
        ++b;
        
        int x = getIndex(input.nextInt());
        int y = getIndex(input.nextInt());

        if(x == y-1){
            System.out.println("YES");
        }else{
            out.println("NO");
        }

        
        
        out.flush();
    }
    
    private static int getIndex(int n){
        for(int i=0;i<arr2.length;++i)
            if(arr2[i]==n)
                return i;
        return -1;
    }
    

}