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.Arrays;
import java.util.Scanner;

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author Eslam Ashraf
 */
public class A69 {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);

        int  n = in.nextInt();
        int m = in.nextInt();


        ArrayList<Integer> a = seive(100);
        int i =0;
        for ( i = 0; i < a.size(); i++) {
            if(a.get(i)==n)break;
        }

        if(a.get(i+1)==m)System.out.println("YES");
        else System.out.println("NO");



    }

      public static  ArrayList<Integer> seive(int cap){
        ArrayList<Integer> primes = new ArrayList<Integer>();
        boolean [] isPrime = new boolean [cap+1];
        Arrays.fill(isPrime, true);
        isPrime[0]=false; isPrime[1]=false;
        for(long i =2 ; i<= cap ;i++)
            if(isPrime[(int)i]){
                primes.add((int)i);
                for(long j =i*i ; j <=cap ; j+=i)isPrime[(int)j]=false;
            }

        return primes;
    }

}
