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.io.PrintWriter;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.StringTokenizer;

public class panaramics implements Runnable {

    private BufferedReader br = null;
    private PrintWriter pw = null;
    private StringTokenizer stk = new StringTokenizer("");

    public static void main(String[] lala) {
        (new Thread(new panaramics())).run();
    }

    public void nline() {
        try {
            while (!stk.hasMoreTokens()) {
                stk = new StringTokenizer(br.readLine());
            }
        } catch (Throwable e) {
            throw new RuntimeException("I wanna be cousmonout", e);
        }

    }

    public String nstr() {
        nline();
        return stk.nextToken();
    }

    public int ni() {
        nline();
        return Integer.valueOf(nstr());
    }

    public double nd() {
        nline();
        return Double.valueOf(nstr());
    }

    public BigInteger nbi() {
        nline();
        return new BigInteger(nstr());
    }

    public void run() {

        br = new BufferedReader(new InputStreamReader(System.in));
        pw = new PrintWriter(System.out);

        solve();
        pw.close();
    }
    boolean p(int a) {
    boolean flag=true;
    for (int i=2; i<Math.sqrt(a)+1; i++){
        if (a % i==0) return false;
    
        
        
        }return flag;   
    }
        
        
    public void solve() {
        int n=ni(), m=ni();
    // if (p(m)!=false) {
        // System.out.println("NO");
         //exit();
     //}
     int k=0;
     for (int i=n+1; i<50; i++){
         if (p(i)==true) {
             k=i;
             break;
         }
         
     }
     if (m==k) System.out.println("YES"); else System.out.println("NO");
     
    }
    public void exit() {
        System.exit(0);
    }
}
