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.*;
import java.util.*;
import java.math.BigInteger;

public class Main {
  public static PrintWriter out;
  public static void main(String[] args) {
    MyScanner sc = new MyScanner();
    out = new PrintWriter(new BufferedOutputStream(System.out));
    int a = sc.nextInt();
    int b = sc.nextInt();
    if (nextPrime(a) == b)
      out.println("YES");
    else
      out.println("NO");
    out.close();
  }

  public static int nextPrime(int a) {
    while (true) {
      a += 1;
      if (BigInteger.valueOf(a).isProbablePrime(10))
        return a;
    }
  }


  public static class MyScanner {
    BufferedReader br;
    StringTokenizer st;

    public MyScanner() {
       br = new BufferedReader(new InputStreamReader(System.in));
    }
 
    public boolean hasNext() {
      try {
        boolean a = br.ready();
        return a;
      } catch (IOException e) {
        return false;
      }
    }

    public String next() {
      while (st == null || !st.hasMoreElements()) {
        try {
          st = new StringTokenizer(br.readLine());
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
      return st.nextToken();
    }
 
    public int nextInt() {
      return Integer.parseInt(next());
    }
 
    public long nextLong() {
      return Long.parseLong(next());
    }

    public double nextDouble() {
      return Double.parseDouble(next());
    }

    public char nextChar() {
      return next().charAt(0);
    }

    public String nextLine() {
      String str = "";
      try {
         str = br.readLine();
      } catch (IOException e) {
         e.printStackTrace();
      }
      return str;
    }
  }
}
