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;

/**
 * @author Nil_ct
 * 19 avr. 2011
 */
public class PanoramixPred {
    int N;
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    String[] tok;
    int[] primes= new int[] {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47};

    private int getInt() throws IOException { return Integer.valueOf(br.readLine());}
    private int toInt(int n) { return Integer.valueOf(tok[n]);}

    private String[] getTok() throws IOException { return br.readLine().split(" ");}
    private int[] getInt(int N) throws IOException { int[] data= new int[N]; tok= br.readLine().split(" "); for (int i=0; i<N; i++) data[i]= Integer.valueOf(tok[i]); return data; }

    public void solve() throws IOException {
        int i=0, j=0;
        int[] n= getInt(2);
        N= n[0];
        int M= n[1];
        while (i< primes.length && primes[i]!= N) ++i;
        if (i<primes.length-1 && primes[i+1]== M) System.out.printf("YES\n"); else System.out.printf("NO\n");
    }


    public static void main(String[] args) throws IOException {
        new PanoramixPred().solve();
    }
}
