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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.StringTokenizer;


public class noAs {
	
	
	public static void main(String[] args) throws NumberFormatException, IOException {
		BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
		int n=100;
		boolean [] x= new boolean [n+1];
		x[0]=true;
		x[1]=true;
		ArrayList<Integer>primes= new ArrayList<Integer>();
		for(int i=2;i<=n;i++){
			if (!x[i]){
				primes.add(i);
			for(int j=2; i*j<=n;j++){
				x[i*j]=true;
			}
			}
		}
		String s= bf.readLine();
	StringTokenizer st= new StringTokenizer(s);
	int f= Integer.parseInt(st.nextToken());
	int y= Integer.parseInt(st.nextToken());
	for (int i = 0; i < args.length; i++) {
		
	}
	boolean p=true;
	for (int i = f+1; i < y; i++) {
		if(primes.contains(i)){
			p=false;
		}
	}
	
	if(p&& primes.contains(y))
		System.out.println("YES");
	else
		System.out.println("NO");
}
}



