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;
/**
 * http://codeforces.com/problemset/problem/80/A
 * Panoramix's Prediction
 */
public class A80 {

		private static boolean isPrime[] = primeSieve(50);;
		
		public static void main(String[] args) throws IOException {
			solve();
		}
		
		public static void solve() throws IOException {
			BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
			String in[] = reader.readLine().split(" ");
			int n = Integer.parseInt(in[0]);
			int m = Integer.parseInt(in[1]);
			
			for(int i = n+1; i <= m; i++){
				if(isPrime[i]){
					if(i == m){
						System.out.println("YES");
						return;
					}else{
						System.out.println("NO");
						return;
					}
				}
			}
			System.out.println("NO");
				
		}
		
		private static boolean[] primeSieve(int N) {

	        // initially assume all integers are prime
	        boolean[] isPrime = new boolean[N + 1];
	        for (int i = 2; i <= N; i++) {
	            isPrime[i] = true;
	        }

	        // mark non-primes <= N using Sieve of Eratosthenes
	        for (int i = 2; i*i <= N; i++) {

	            // if i is prime, then mark multiples of i as nonprime
	            // suffices to consider mutiples i, i+1, ..., N/i
	            if (isPrime[i]) {
	                for (int j = i; i*j <= N; j++) {
	                    isPrime[i*j] = false;
	                }
	            }
	        }

	        return isPrime;
		}
}
