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;

public class Test {
    static int[] arr = new int[15];
    static void setup(){
        arr[0] = 2;
        arr[1] = 3;
        arr[2] = 5;
        arr[3] = 7;
        arr[4] = 11;
        arr[5] = 13;
        arr[6] = 17;
        arr[7] = 19;
        arr[8] = 23;
        arr[9] = 29;
        arr[10] = 31;
        arr[11] = 37;
        arr[12] = 41;
        arr[13] = 43;
        arr[14] = 47;
    }
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        setup();
        int n = sc.nextInt();
        int m = sc.nextInt();
        boolean flag = false;
        for (int i = 0; i < 14; i++) {
            if (n==arr[i] && m==arr[i+1]){
                flag = true;
                break;
            }
        }
        if (flag){
            System.out.println("YES");
        }else{
            System.out.println("NO");
        }
    }
}
