#include <bits/stdc++.h>
using namespace std;
#define int long long
#define rep(i, a, b) for (int i = (int)(a); i < (int)(b); ++i)
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;
}

map<int, int> factorize(int a) {
    map<int, int> ret;
    for(int i = 2; i * i <= a; i++) {
        int cnt = 0;
        while (a % i == 0) a /= i, cnt++;
        if (cnt != 0) ret[i] = cnt;
    }
    if (a != 1) ret[a] = 1;
    return ret;
}

signed main() {
    int N, K;
    cin >> N >> K;
    int ans = 0;
    int cnt = 0;
    auto F = factorize(N);
    rep(i, 1, N) {
        auto f = factorize(i);
        int tmp = 1;
        int tmp2 = 0;
        for (auto p : f) {
            tmp *= p.second + 1;
            tmp2 += min(F[p.first], p.second);
        }
        if (tmp2 < K) continue;
        if (chmax(cnt, tmp)) {
            ans = i;
        }
    }
    cout << ans << endl;
}