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
/**
 * Created by mahsa on 8/19/2018.
 */
import java.util.*;
public class Main {
    public static void main(String[] args){
        Scanner input=new Scanner(System.in);
        boolean b=false,c=false,e=false;
        int n=input.nextInt();
        int a=0,d=0;
        int m=input.nextInt();
        int j=n+1;
        for(int i=2;i<n;i++){
            if(n%i==0)
                b=true;
        }
        if(b==false) {
            for (int l = 2; l < m; l++) {
                if (m % l == 0)
                    e = true;
            }
            if (e == false) {
                for (j = n + 1; j <m; j++) {
                    for (int k = 2; k <= m / 2; k++) {
                        if (j % k == 0)
                            a++;
                    }
                    if (a >= 1)
                        c = true;
                    else
                        c = false;
                    a = 0;
                    if (c == false)
                        d++;


                }
            }
        }
        if(d==0 && b==false && e==false)
            System.out.print("YES");
        else
            System.out.print("NO");
    }
}
