#include "bits/stdc++.h"

using namespace std;
#ifdef _DEBUG
#define _GLIBCXX_DEBUG
#include "dump.hpp"
#else
#define dump(...)
#endif

#define int long long
#define ll long long
#define DBG 1
#define rep(i, a, b) for (int i = (a); i < (b); i++)
#define rrep(i, a, b) for (int i = (b)-1; i >= (a); i--)
#define loop(n) rep(loop, (0), (n))
#define all(c) begin(c), end(c)
const int INF = sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = (int)(1e9) + 7;
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
using pii = pair<int, int>;
// template<class T> ostream &operator<<(ostream &os,T &t){dump(t);return os;}
template <typename T, typename S>istream &operator>>(istream &is, pair<T, S> &p) { is >> p.first >> p.second; return is; }
template <typename T, typename S>ostream &operator<<(ostream &os, pair<T, S> &p) { os << p.first << " " << p.second; return os; }

template <typename T> void printvv(const vector<vector<T>> &v) {
	cerr << endl;
	rep(i, 0, v.size()) rep(j, 0, v[i].size()) {
		if (typeid(v[i][j]).name() == typeid(INF).name() and v[i][j] == INF) {
			cerr << "INF";
		}
		else
			cerr << v[i][j];
		cerr << (j == v[i].size() - 1 ? '\n' : ' ');
	}
	cerr << endl;
}

#ifndef _DEBUG
#define printvv(...)
#endif
void YES(bool f) { cout << (f ? "YES" : "NO") << endl; }
void Yes(bool f) { cout << (f ? "Yes" : "No") << endl; }
template <class T> bool chmax(T &a, const T &b) { if (a < b) { a = b; return true; }return false; }
template <class T> bool chmin(T &a, const T &b) { if (a > b) { a = b; return true; }return false; }

vector<int> prime_factorization(int x) {
	vector<int> min_fact(x + 1);
	min_fact[1] = 1;
	for (int i = 2; i <= x; i++) {
		if (min_fact[i] != 0)
			continue;
		for (int j = i; j <= x; j += i) {
			if (min_fact[j] == 0)
				min_fact[j] = i;
		}
	}
	vector<int>fact;
	while (x > 1) {
		int f = min_fact[x];
		fact.emplace_back(f);
		x /= f;
	}
	return fact;
}
signed main(signed argc, char *argv[]) {
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout << fixed << setprecision(12);

	int N, K; cin >> N >> K;
	int x = N;
	vector<int> min_fact(x + 1);
	min_fact[1] = 1;
	for (int i = 2; i <= x; i++) {
		if (min_fact[i] != 0)
			continue;
		for (int j = i; j <= x; j += i) {
			if (min_fact[j] == 0)
				min_fact[j] = i;
		}
	}
	map<int, int>mp;
	while (x > 1) {
		int f = min_fact[x];
		mp[f]++;
		x /= f;
	}
	int ans = 0;
	int cnt = 0;
	rep(i, 1, N) {
		map<int, int>mp2;
		int x = i;
		while (x > 1) {
			int f = min_fact[x];
			mp2[f]++;
			x /= f;
		}
		int y = 1;
		int common = 0;
		for (auto p : mp2) {
			common += min(p.second, mp[p.first]);
			y *= p.second + 1;
		}
		if (common >= K and chmax(cnt, y))ans = i;
	}
	cout << ans << endl;

	return 0;
}