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.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.StringTokenizer;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.InputStream;
import java.util.ArrayList;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author _disturbed_
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        FastScanner in = new FastScanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        APanoramixsPrediction solver = new APanoramixsPrediction();
        solver.solve(1, in, out);
        out.close();
    }

    static class APanoramixsPrediction {
        public void solve(int testNumber, FastScanner fs, PrintWriter out) {
            int n = fs.nextInt(), m = fs.nextInt();
            int[] primes = Sieve.getPrimes(100);

            int idx = -1;
            for (int i = 0; i < primes.length; i++) {
                if (primes[i] == n) {
                    idx = i;
                    break;
                }
            }

            out.println(primes[idx + 1] == m ? "YES" : "NO");
        }

    }

    static class Sieve {
        public static boolean[] getSieve(int n) {
            boolean[] sieve = new boolean[n + 1];
            Arrays.fill(sieve, true);
            sieve[0] = sieve[1] = false;

            for (int i = 2; i <= n; i++) {
                if (sieve[i] && (long) i * i <= n) {
                    for (int j = i * i; j < n; j += i) {
                        sieve[j] = false;
                    }
                }
            }

            return sieve;
        }

        public static int[] getPrimes(int n) {
            boolean[] sieve = getSieve(n);
            ArrayList<Integer> prime = new ArrayList<>();

            for (int i = 2; i <= n; i++) {
                if (sieve[i]) {
                    prime.add(i);
                }
            }

            int[] primes = new int[prime.size()];
            for (int i = 0; i < primes.length; i++) {
                primes[i] = prime.get(i);
            }

            return primes;
        }

    }

    static class FastScanner {
        BufferedReader br;
        StringTokenizer st;

        public FastScanner(InputStream inputStream) {
            br = new BufferedReader(new InputStreamReader(inputStream));
        }

        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());
        }

    }
}

