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.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.StringTokenizer;

public class Main {

	public static void main(String[] args) {
			
		InputReader in = new InputReader(System.in);
		int n1,n2;
		n1 = in.nextInt();
		n2= in.nextInt();
		ArrayList<Integer> primes = new ArrayList<>();
		for(int i=2;i<50;i++) {
			for(int j =2;j<50;j++) {
				if(i!=j) {
					if(i%j==0)
						break;
				}
				
				if(j==49) {
					primes.add(i);
				}
			}
			
		}
		
		
		if(n1 < 47) {
			for(int i =0;i<primes.size();i++) {
				if(primes.get(i).equals(n1)) {
					if(primes.get(i+1).equals(n2)) {
						System.out.println("YES");
						break;

					}
					else {
						System.out.println("NO");
						break;
					}
				}
			}
			
		}else {
			System.out.println("NO");
		}
		
		
	
			
			
		}
		
		
		
	
	

	 static class InputReader {
	        public BufferedReader reader;
	        public StringTokenizer tokenizer;

	        public InputReader(InputStream stream) {
	            reader = new BufferedReader(new InputStreamReader(stream), 32768);
	            tokenizer = null;
	        }

	        public String next() {
	            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
	                try {
	                    tokenizer = new StringTokenizer(reader.readLine());
	                } catch (IOException e) {
	                    throw new RuntimeException(e);
	                }
	            }
	            return tokenizer.nextToken();
	        }

	        public int nextInt() {
	            return Integer.parseInt(next());
	        }
	        
	        public long nextLong() {
	            return Long.parseLong(next());
	        }

	    }
	 
	 }



