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
/* package codechef; // don't place package name! */
import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
public class Codechef
{
	public static void main (String[] args) throws java.lang.Exception
	{
	   Scanner Sc=new Scanner(System.in);
	   int n=Sc.nextInt();
	   int m=Sc.nextInt();
	   int flag=0;
	   for(int i=n+1;i<=m;i++)
	   {
	       int c=0;
	       for(int j=2;j<i;j++)
	       {
	           if(i%j==0)
	           {
	           c++;
	           break;
	           }
	       }
	       if(c==0&&i==m)
	       {
	           System.out.println("YES");
	           flag=1;
	           break;
	       }
	       else if(c==0&&i!=m)
	       {
	           flag=2;
	           break;
	       }
	   }
	   if(flag==0||flag==2)
	    System.out.println("NO");
	}
}