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.math.*;
import java.util.*;

public class Main implements Runnable {
	String file = "template";

	private void solve() throws IOException {
		int n = nextInt();
		int m = nextInt();
		for (int i = n + 1; i < m; ++i) {
			boolean ok = true;
			for (int j = 2; j * j <= i; ++j) {
				if (i % j == 0) {
					ok = false;
				}
			}
			if (ok) {
				out.println("NO");
				return;
			}
		}
		for (int j = 2; j * j <= m; ++j) {
			if (m % j == 0) {
				out.println("NO");
				return;
			}
		}
		out.println("YES");
	}

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

	BufferedReader br;
	StringTokenizer tok;
	PrintWriter out;

	public void run() {
		try {
			Locale.setDefault(Locale.US);
			if (Boolean.getBoolean("SpbAU")) {
				br = new BufferedReader(new FileReader(file + ".in"));
				out = new PrintWriter(System.out);
			} else {
				br = new BufferedReader(new InputStreamReader(System.in));
				out = new PrintWriter(System.out);
			}
			tok = new StringTokenizer("");
			while (hasNext()) {
				solve();
			}
			out.close();
		} catch (Exception e) {
			e.printStackTrace();
			System.exit(1);
		}
	}

	boolean hasNext() throws IOException {
		while (!tok.hasMoreElements()) {
			String line = br.readLine();
			if (line == null) {
				return false;
			}
			tok = new StringTokenizer(line);
		}
		return true;
	}

	String next() throws IOException {
		if (hasNext()) {
			return tok.nextToken();
		}
		throw new IOException("No more tokens");
	}

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

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

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