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.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author Tushar Paliwal
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        APanoramixsPrediction solver = new APanoramixsPrediction();
        solver.solve(1, in, out);
        out.close();
    }

    static class APanoramixsPrediction {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int x = in.nextInt(), y = in.nextInt();
            if (result(x, y)) {
                out.print("YES");
            } else {
                out.print("NO");
            }
        }

        public boolean result(int x, int y) {
            int result = x + 1;
            for (int i = result; i <= y; i++) {
                if (checkPrime(i)) {
                    result = i;
                    break;
                }
            }

            if (result == y && checkPrime(y)) {
                return true;
            } else {
                return false;
            }
        }

        public boolean checkPrime(int n) {
            if (n % 2 == 0) {
                if (n == 2) {
                    return true;
                } else {
                    return false;
                }
            } else {
                for (int i = 3; i * i <= n; i += 2) {
                    if (n % i == 0 && i != n) {
                        return false;
                    }
                }
            }

            return true;
        }

    }
}

