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 A80PanoramixsPrediction {
	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader( new InputStreamReader(System.in));
	String line[] = br.readLine().split(" " );
	int n =Integer.parseInt(line[0]);
	int m=Integer.parseInt(line[1]);
	boolean f=true;
	for(int i=n+1;i<m;i++)
	{
		if(isPrime (i))
		{	f=false;
			break;
		}
	}
	if(f&&isPrime(m))
	{
		System.out.println("YES");
	}
	else
	{
		System.out.println("NO");
	}
	}

	private static boolean isPrime(int n) {
		for(int i=2;i<n;i++)
		{
			if(n%i==0)
			{
				return false;
			}
		}
		return true;
	}
}
