import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String s = br.readLine().replace(" ", "");
		int md = Integer.parseInt(s);
		br.close();

		if (isSosuu(md)) {
			System.out.println("Yes");
		} else {
			System.out.println("No");
		}
	}

	static boolean isSosuu(long n) {
		if (n < 2) return false;
		if (n == 2) return true;
		long end = (int) Math.sqrt(n) + 1;
		for (int i = 2; i <= end; i++) {
			if (n % i == 0) {
				return false;
			}
		}
		return true;
	}
}