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.*;
import java.lang.reflect.Array;
import java.util.*;
import java.lang.*;
import java.util.stream.IntStream;
import java.util.stream.Stream;

public class Main {

    private static final Scanner scanner = new Scanner(System.in);

    public static void main(String[] args) throws IOException {
        int n = scanner.nextInt();
        scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");
        int m = scanner.nextInt();
        scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");

        String result = "YES";
        if (isPrime(m)) {
            while (n + 1 < m--) {
                if (isPrime(m)) {
                    result = "NO";
                    break;
                }
            }
        }
        else {
            result = "NO";
        }

        System.out.println(result);

    }
	
	public static boolean isPrime(int n) {
        boolean isPrime = true;
        if (n == 1 || n == 0 || n > 2 && n % 2 == 0) {
            isPrime = false;
        } else {
            for (int i = 2; i <= Math.sqrt(n); i++) {
                if (n % i == 0) {
                    isPrime = false;
                    break;
                }
            }
        }

        return isPrime;
    }

}