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.ArrayList;
import java.util.Scanner;

public class Panoramixs_Prediction {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
     	int n,m ;
		Scanner sc = new Scanner(System.in);
		ArrayList<Integer> prime=sieve(50);
			while(sc.hasNext())
			{
				 n=sc.nextInt();
				 m=sc.nextInt();
			   
			   if(prime.indexOf(m)==prime.indexOf(n)+1) System.out.println("YES");
			   else System.out.println("NO");
			}
	}
	 public static ArrayList<Integer> sieve(int n)
	{
		ArrayList<Integer> premiers = new ArrayList<Integer>();
	   boolean[] prime=new boolean[n+1];
 	   int m=(int)Math.sqrt(n);
	   for (int i=2; i<=m; i++)
	      if (!prime[i])
	      {  premiers.add(i);
	         for (int k=i*i; k<=n; k+=i)
	            prime[k]=true;
	      }
	   for(int i=m+1;i<=n;i++)
	   {
		   if(!prime[i]) premiers.add(i);
	   }

	   return premiers;
	} 

}
