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.*;


public class PanoramixPrediction {

    public static void main(String args[]) {

        FastReader sc = new FastReader();
        PrintWriter out = new PrintWriter(System.out);

        int t, n, i, j,m;
        String s;

        n = sc.nextInt();
        m = sc.nextInt();
        List<Integer> list = new ArrayList<>();

        for (i = 2; i <= m; i++) {
            int flag=0;
            for (j = 2; j<=i/2 ; j++) {
                if(i%j==0){
                    flag=1;
                    break;
                }
            }
            if(flag==0)
            list.add(i);
        }
        if (!list.contains(m))
        out.println("NO");
        else{
            if(list.get(list.size()-2)==n)
                out.println("YES");
            else
                out.println("NO");
        }

        out.close();
    }


    /*
		FASTREADER
	*/
    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

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

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

        long nextLong() {
            return Long.parseLong(next());
        }

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

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

        /*DEFINED BY ME
         */
        int[] readArray(int n) {

            int arr[] = new int[n];

            for (int i = 0; i < n; i++)
                arr[i] = nextInt();

            return arr;
        }
    }
}