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;

/**
 *
 * @author Alex
 */
public class PanoramixsPrediction {

    
    public static void main(String[] args) {
       Scanner in=new Scanner(System.in);
       int n=in.nextInt();
       int m=in.nextInt();
       int nextprime = 0;
       int i;
        switch (n) {
            case 2:
                nextprime=3;
                break;
            case 3:
                nextprime=5;
                break;
            default:
                for(i=n+2;i<50;i+=2){
                    if(nextprime(i)){
                        nextprime=i;
                        break;
                    }
                }    break;
        }
       if(nextprime==m){
           System.out.println("YES");
       }else{
           System.out.println("NO");
       }
    }
    public static boolean nextprime(int x){
        int j;
        boolean status=true;
        if(x%2==0){
            return false;
        }else{
             for(j=3;j<=Math.sqrt(x);j+=2){
                    if(x%j==0){
                     status=false;
                     break;   
                    }
                }
            
        }
        return status;
    }
    
}