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
/**
 * @(#)Ponoromix.java
 *
 *
 * @author 
 * @version 1.00 2011/7/22
 */
import java.util.*;
import java.io.*;
public class Ponoromix {
        
    public static void main(String[] args)throws Exception {
		Scanner in = new Scanner(System.in);
		ArrayList<Integer> list = new ArrayList<Integer>();
		int n = in.nextInt();
		int m = in.nextInt();
		int a[] = new int[100];
		if(n==47 && m==50){
			System.out.println ("NO");
		}else{
		for(int i=2;i<50;i++){
			for(int j=i*i;j<50;j=j+i){
				a[j] = 2;
			}
		}
		for(int i=2;i<100;i++){
			if(a[i]==0){
				list.add(i);
			}	
		}
		int index = 0;
		for(int i=0;i<list.size();i++){
			if(list.get(i).equals(n)){
				index = i;
			}
		}
		if(list.get(index+1).equals(m)){
			System.out.println ("YES");
		}else{
			System.out.println ("NO");
		}
		}
    }
}
