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 Main {
    private static Scanner input = new Scanner(System.in);
    private static int fNumber;
    private static int sNumber;

    public static void main(String[] args) {
        enterValues();
        if (numbersIsPrime(fNumber) || numbersIsPrime(sNumber)) {
            System.out.println("NO");
            return;
        } else {
            getTheSecondPrime(fNumber, sNumber);
        }
    }
    private static void getTheSecondPrime(int fNumber2, int sNumber2) {
        while (true) {
            if (!numbersIsPrime(++fNumber2)) {
                if (fNumber2 == sNumber2) {
                    System.out.println("YES");
                    break;
                } else {
                    System.out.println("NO");
                    break;
                }
            }
        }

    }

    private static boolean numbersIsPrime(int number) {
        if ((number % 2 == 0 && number != 2)
                || (number % 3 == 0 && number != 3)
                || (number % 4 == 0 && number != 4)
                || (number % 5 == 0 && number != 5)
                || (number % 6 == 0 && number != 6)
                || (number % 7 == 0 && number != 7)
                || (number % 8 == 0 && number != 8)
                || (number % 9 == 0 && number != 9)) {
            return true;
        }
        return false;
    }
    private static void enterValues() {
        fNumber = input.nextInt();
        sNumber = input.nextInt();
    }
}