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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class A_69_PanoramixsPrediction {
    public static void main(String[] args) {
        try {
            BufferedReader input = new BufferedReader(new InputStreamReader(
                    System.in));
            String line = input.readLine();
            String[] strNums = line.split(" ");
            int x = Integer.parseInt(strNums[0]);
            int y = Integer.parseInt(strNums[1]);

            if (isPrime(x) && isPrime(y)) {
                if (x + 1 == y || x + 2 == y) {
                    System.out.println("YES");
                    System.exit(0);
                }

                int tmpNum = (x % 2 == 0) ? x + 1 : x + 2;
                for (; tmpNum < y; tmpNum += 2) {
                    if (isPrime(tmpNum)) {
                        System.out.println("NO");
                        System.exit(0);
                    }
                }

                System.out.println("YES");
                System.exit(0);
            }

            System.out.println("NO");
            System.exit(0);

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private static boolean isPrime(int num) {
        if (num == 2) {
            return true;
        }
        if (num % 2 == 0) {
            return false;
        }
        int upbound = num / 2 + 1;
        for (int i = 3; i < upbound; i += 2) {
            if (num % i == 0) {
                return false;
            }
        }

        return true;
    }
}
