#include <algorithm>
#include <iostream>
#include <iterator>
#include <utility>
#include <vector>
using namespace std;

int main() {
	int N, K, i = 2;
	cin >> N >> K;
	int a = N;
	pair<int, int> b;
	vector<int> c;
	while (a >= i * i) {
		if (0 == a % i) {
			a /= i;
			c.push_back(i);
		}
		else ++i;
	}
	c.push_back(a);
	for (i = 1; i < N; ++i) {
		a = i;
		int d = 0, j = 2;
		vector<int> e, f;
		while (a >= j * j) {
			if (0 == a % j) {
				a /= j;
				e.push_back(j);
			}
			else ++j;
		}
		e.push_back(a);
		set_intersection(c.begin(), c.end(), e.begin(), e.end(), inserter(f, f.end()));
		if (K <= f.size()) {
			for (j = 1; j * j <= i; ++j) {
				if (0 == i % j) {
					++d;
					if (i / j != j) ++d;
				}
			}
			if (b.first < d) {
				b.first = d;
				b.second = i;
			}
		}
	}
	cout << b.second;
}