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;
import java.util.StringTokenizer;

/**
 *
 * @author sukhdeep
 */
public class Test {

    public static void main(String ar[]) throws IOException {
        BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
        
       
               

StringTokenizer str=new StringTokenizer(r.readLine());

int n=Integer.parseInt(str.nextToken());
int m=Integer.parseInt(str.nextToken());
int flag=1;
for(int i=n+1;i<=m;i++)
{
    if(isPrime(i))
    {
        if(i==m)
            flag=0;
        break;
        
    }
    
}if(flag==0)
    System.out.println("YES");
else
        System.out.println("NO");


} 

  public static boolean isPrime (int x)
    {
        for (int i= 2;i<=Math.sqrt(x);i++)
        {
            if (x%i==0)
            {
                return false;
            }
        }

        return true;
    }
} 