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.Collections;
    import java.util.StringTokenizer;

    public class Main implements Runnable {
        private void solve() throws IOException {
            int a=nextInt();
            int b=nextInt();
            int ans=0;
            for(int j=a+1;j<=b;j++)
                if(isPrime(j))
                    ans++;
            if(ans==1 && isPrime(b))writer.println("YES");
            else writer.println("NO");
            
        }
        
        public boolean isPrime(int n){
            if(n==2)return true;
            if(n%2==0)return false;
            for(int i=3;i*i<=n;i+=2)
                if(n%i==0)
                    return false;
            return true;
        }

        public static void main(String[] args) {
            new Main().run();
        }

        BufferedReader reader;
        StringTokenizer tokenizer;
        PrintWriter writer;

        public void run() {
            try {
                reader = new BufferedReader(new InputStreamReader(System.in));
                tokenizer = null;
                writer = new PrintWriter(System.out);
                solve();
                reader.close();
                writer.close();
            } catch (Exception e) {
                e.printStackTrace();
                System.exit(1);
            }
        }

        int nextInt() throws IOException {
            return Integer.parseInt(nextToken());
        }

        long nextLong() throws IOException {
            return Long.parseLong(nextToken());
        }
        BigInteger nextBigInteger() throws IOException{
            return new BigInteger(nextToken());
        }
        double nextDouble() throws IOException {
            return Double.parseDouble(nextToken());
        }

        String nextToken() throws IOException {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                tokenizer = new StringTokenizer(reader.readLine());
            }
            return tokenizer.nextToken();
        }
    }
