import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int a = sc.nextInt();
		int b = sc.nextInt();
		sc.close();

		long ans = 0;
		for (int i = a; i <= b; i++) {
			if (isSosuu(i)) {
				ans += i * i * i - i * i + i + 1;
			}
		}
		System.out.println(ans);
	}

	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;
	}
}