#include <bits/stdc++.h>
using namespace std;

vector<int> factorize(int N){
    vector<int> fs;
    for (int f = 2; f*f <= N; ++f){
        while (N % f == 0){
            fs.push_back(f);
            N /= f;
        }
    }
    if (N > 1) fs.push_back(N);
    return fs;
}

bool has_K_common_factors(int n, int K, const vector<int> &fs){
    for (auto f : fs){
        if (n % f == 0){
            n /= f;
            --K;
        }
    }
    return K <= 0;
}

int count_divisors(int n){
    int n_div = 1;
    for (int f = 2; f*f <= n; ++f){
        int c = 1;
        while (n % f == 0){
            ++c;
            n /= f;
        }
        n_div *= c;
    }
    if (n > 1) n_div *= 2;
    return n_div;
}

int solve(int N, int K){
    int max_n_div = 1;
    int ans = 1;
    auto fs = factorize(N);
    for (int i = 2; i < N; ++i){
        if (has_K_common_factors(i, K, fs)){
            int n_div = count_divisors(i);
            if (n_div > max_n_div){
                ans = i;
                max_n_div = n_div;
            }
        }
    }
    return ans;
}

int main()
{
    ios::sync_with_stdio(false);
    cout.tie(0);
    int N, K;
    cin >> N >> K;
    cout << solve(N, K) << endl;
    return 0;
}