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.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.BitSet;
import java.util.StringTokenizer;
import java.util.regex.Matcher;
import java.util.regex.Pattern;


public class sol {
	//...................... Global Variables .......................//
	static BitSet prime;             // used in seive generation
	// true = not prime     and false = prime
	int prev_avg = 0;
	int n = 0;
	//...................... Global Variables .......................//
	
	
	
	
	
	//===================  PROBLEM SOLVING COMES HERE ===== START  ====================//
	
    void solve() throws IOException, Exception {
      
    	int[] array = {2, 2, 3, 5, 5, 7, 7, 11, 11, 11, 11, 13, 13, 17, 17, 17, 17, 19, 19, 23, 23, 23, 23, 29, 29, 29, 29, 29, 29, 31, 31, 37, 37, 37, 37, 37, 37, 41, 41, 41, 41, 43, 43, 47, 47, 47, 47, 53, 53, 53, 53, 53, 53};
        int m = in.nextInt();
        int n = in.nextInt();
        if(n == array[m])
            System.out.println("YES");
        else
            System.out.println("NO");
    }
    

    //===================  PROBLEM SOLVING COMES HERE ===== END ======================//
    
    
    
    
    
    
    public static void main(String[] args) throws FileNotFoundException, IOException, Exception {
    	
    	//--------------------------------- Console I/O ------------------------------//
    	   in = new FastScanner(new BufferedReader(new InputStreamReader(System.in)));
           out = new PrintWriter(System.out);
    	//--------------------------------- Console I/O ------------------------------//
    	
    	
    	//--------------------------------- File I/O ---------------------------------//
        //   in = new FastScanner(new BufferedReader(new FileReader("input.txt")));
        //   out = new PrintWriter(new FileWriter("output.txt"));
        //--------------------------------- File I/O ---------------------------------//
        new sol().solve();
        out.close();
    }
    
    
    

		 
		 
		 
		 
    static FastScanner in;
    static PrintWriter out;

    static class FastScanner {
        BufferedReader in;
        StringTokenizer st;

        public FastScanner(BufferedReader in) {
            this.in = in;
        }

        public String nextToken() {
            while (st == null || !st.hasMoreTokens()) {
                try {
                    st = new StringTokenizer(in.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        public int nextInt() { return Integer.parseInt(nextToken()); }
        public long nextLong() { return Long.parseLong(nextToken()); }
        public double nextDouble() { return Double.parseDouble(nextToken()); }
        public BigInteger BigInteger()throws Exception { return new BigInteger(nextToken()); }
        public String next() throws IOException { return nextToken(); }
        public String nextLine() throws IOException { return in.readLine(); }
        
        public int[] readIntArray(int n) {
            int[] ret = new int[n];
            for (int i = 0; i < n; i++) {
                ret[i] = nextInt();
            }
            return ret;
        }
        
        public void printIntArray(int ar[],int n) {
            for (int i = 0; i < n; i++) {
                System.out.print(ar[i] +" ");
            }System.out.println();
        }
        
    }
}