#include "bits/stdc++.h"

using namespace std;

vector<pair<int, int>> factors(int x)
{
	vector<pair<int, int>> ps;
	for (int i = 2; i * i <= x; i++)
	{
		if (x % i) continue;
		int cnt = 0;
		while(x % i == 0)
		{
			cnt++;
			x /= i;
		}
		ps.push_back({i, cnt});
	}
	if (x > 1) ps.push_back({x, 1});
	return ps;
}

void solve()
{
	int n, k;
	cin >> n >> k;
	int ans = 0, maxi = 0;
	for (int x = 1; x < n; x++)
	{
		int g = __gcd(x, n);
		auto gp = factors(g);
		int cnt = 0;
		for (auto p : gp)
		{
			cnt += p.second;
		}
		if (cnt < k) continue;
		auto ps = factors(x);
		int m = 1;
		for (auto p : ps)
		{
			m *= p.second + 1;
		}
		if (m > maxi)
		{
			maxi = m;
			ans = x;
		}
	}
	cout << ans << endl;
}

int main()
{
	solve();
	//cout << "yui(*-v・)yui" << endl;
	return 0;
}