#include <iostream>
using namespace std;

int p_gcd(int m);
int gcd(int m, int n);
int root(int n);

int main()
{
	int n;
	int k;
	int ans;
	int m = 0;

	cin >> n >> k;

	for (int i = 2; i < n; i++) {

		if (p_gcd(gcd(i, n)) >= k) {

			int r = root(i);

			if (r > m) {
				m = r;
				ans = i;
			}

		}
	}

	cout << ans << endl;

	return 0;
}

int p_gcd(int m)
{
	int cnt = 0;

	int i = 2;
	while (m > 1) {
		if (m % i == 0) {
			cnt++;
			m /= i;
		} else {
			i++;
		}
	}

	return cnt;
}

int gcd(int m, int n)
{
	if (m < n) {
		int tmp = m;
		m = n;
		n = tmp;
	}

	int r;
	while (n) {
		r = m % n;
		m = n;
		n = r;
	}

	return m;
}

int root(int n)
{
	int cnt = 0;

	for (int i = 1; i * i <= n; i++) {
		if (n % i == 0) {

			if (i * i == n ) {
				cnt += 1;
			} else {
				cnt += 2;
			}
		}
	}

	return cnt;
}