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.*;
import java.lang.*;
import java.io.*;

public class Codechef
{
    static int isprime(int x){
        int flag=0;
        for(int i=3;i<x/2; ){
            if(x%i==0){
                flag=-1;break;
            }
            i+=2;
        }return flag;
    }
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
		Scanner sc=new Scanner(System.in);
		int m=0,n=0;
		if(sc.hasNextInt()){
		    n=sc.nextInt();
		    m=sc.nextInt();
		}
		if(n==2){
		    if(m==3)System.out.println("YES");
		    else System.out.println("NO");
		  
		}else{
		int x=n+2;
		while(isprime(x)==-1 ){
		    x=x+2;
		    if(x>m){
		        break; 
		    }
		}
		if(x==m) System.out.println("YES");
		else System.out.println("NO"); 	}
	}
}
