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.Scanner;
import java.util.Vector;

public class NewClass19 {
//  static int n;
    static boolean a[] = new boolean[100000];
    
    public static void main(String[] args) {
        Scanner ob = new Scanner(System.in);
        int x=ob.nextInt();
        int y=ob.nextInt();
        
       int  n = 100;
         Vector v=new Vector();
        for (int i = 0; i <= n; i++) {
            a[i] = true;
        }
        for(int i=2;i<=n;i+=2){a[i]=false;}
        for (int i = 3; i < Math.sqrt(n); i++) {
            if (a[i] == true) {
                for (int j = i * i; j <= n; j = j + i) {
                    a[j] = false;
                }
            }
        }
        v.add(2);
        for(int i=2;i<=n;i++)
        {
        if(a[i]==true){v.add(i);}
        }
      //solve 
      int k=0;
        for(int i=0;i<v.size();i++)
        {
        if(x==(int)v.get(i)&&y==(int )v.get(i+1))
        {
           k=1;
           break;
        }
        }
        if(k==1){System.out.println("YES");}
        else
            System.out.println("NO");
    }
    }
