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.util.*;
public class C {
    static class FastScanner {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer("");

        String next() {
            while (!st.hasMoreTokens())
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            return st.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        int[] nextArray(int n) {
            int[] a = new int[n];
            for (int i = 0; i < n; i++) a[i] = nextInt();
            return a;
        }

        long nextLong() {
            return Long.parseLong(next());
        }
    }
    static class FastWriter extends PrintWriter {
        FastWriter() {
            super(System.out);
        }

        void println(int[] array) {
            for (int i = 0; i < array.length; i++) {
                print(array[i] + " ");
            }
            println();
        }

        void println(long[] array) {
            for (int i = 0; i < array.length; i++) {
                print(array[i] + " ");
            }
            println();
        }
    }
    public static void main(String[] args) {
        // Yo bitch !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
        FastScanner in = new FastScanner();
        FastWriter out = new FastWriter();
//        int t=in.nextInt();
//        while(t-->0){
//            int n=in.nextInt();
//            int[] ar=in.nextArray(n);
//        }
        int n=in.nextInt();
        int m=in.nextInt();
        int i=1;
        for (int j = n+1; j <= m; j++) {
            if(isPrime(j)){
                if(j==m){
                    System.out.println("YES");
                }else{
                    System.out.println("NO");
                }
                return;
            }
        }
        out.println("NO");
        out.close();
    }
    static boolean isPrime(int n) {
        if (n <= 1){
            return false;
        }else if (n == 2){
            return true;
        }else if (n % 2 == 0){
            return false;
        }
        for (int i = 3; i <= Math.sqrt(n); i += 2) {
            if (n % i == 0){
                return false;
            }
        }
        return true;
    }
}