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.io.*;
public class panoramixprediction {

	public static void main(String[] args) throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(br.readLine());
		br.close();
		int n = Integer.parseInt(st.nextToken());
		int m = Integer.parseInt(st.nextToken());
		boolean value = isNextPrime(n,m);
		System.out.println(value ? "YES" : "NO");
	}

	private static boolean isNextPrime(int n, int m) {
		boolean output = false;
		for(int i = n+1; i <= m; i++) {
			if(isPrime(i) && i != m) {
				break;
			}
			else if (i == m) {
				if(isPrime(m)) {
					output = true;
				}
				break;
			}
		}
		return output;
	}

	private static boolean isPrime(int i) {
		boolean output = false;
		int upto = (int)Math.round(Math.sqrt(i));
		
		for(int j = 2; j <= upto; j++) {
			if(i % j == 0) break;
			if(j == upto) {
				output = true;
			}
		}
		return output;
	}

}
