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.IOException;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Scanner;


public class Main
{

    static int[] isPrime;
    
    public static void sieve(int N) {                   //generates all primes [2,N]
        
        isPrime = new int[N+1];         
        isPrime[0] = isPrime[1] = 1;            // 0 indicates a prime number
        
        
        for (long i = 2; i <= N; i++)                   //you can loop till i*i <= N
            if (isPrime[(int)i]==0) 
            {
                
                for (long j = i * i; j <= N; j += i)    //to test primality of N, loop till j*j <= N
                    isPrime[(int)j] = 1;
            }   
    }       
    
    
    public static void main(String[] args) throws NumberFormatException, IOException {
        
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt(), m = sc.nextInt();
        sieve(50);
        
        for(int i = n + 1; i < m; i++)
            if(isPrime[i] == 0)
            {
                System.out.println("NO");
                return;
            }
        if(isPrime[m] == 0)
            System.out.println("YES");
        else
            System.out.println("NO");
        
    }
    
    

}


