import java.util.Scanner;

public class Test {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt(), m = sc.nextInt(), k = m - (n - 1) * 2, t;
		long sum = 0;
		if (k < 0) {
			System.out.println(0);
			return;
		}
		k = m / (n - 1);
		boolean[] b = new boolean[k + 1];
		b[0] = true;
		b[1] = true;
		t = 1;
		while ((t + 1) * (t + 1) <= k) {
			t++;
		}
		for (int i = 2; i <= t; i++) {
			if (b[i]) {
				continue;
			}
			for (int j = i * i; j <= k; j += i) {
				b[j] = true;
			}
		}
		for (int i = 2; i <= k; i++) {
			if (!b[i]) {
				sum += (long) (m - (n - 1) * i + 1);
			}
		}
		System.out.println(sum);
	}
}