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

int main(){
    int n, k;
    cin >> n >> k;
    assert(4 <= n && n <= 100000);
    int f = 0, N = n;
    vector<int> facter(n, 1), prime(n);
    for(int i = 2; i < n; i++) for(int j = i; j < n; j += i) facter[j]++;
    for(int i = 2; i * i <= n; i++) if(n % i == 0) {
        int p = 1;
        while(n % i == 0) {
            f++;
            p *= i;
            n /= i;
            for(int j = p; j < N; j += p) prime[j]++;
        }
    }
    if(n != 1) {
        f++;
        for(int i = n; i < N; i += n) prime[i]++;
    }
    assert(1 <= k && k <= 15 && k < f);
    int max = 0, ans;
    for(int i = 2; i < N; i++) if(prime[i] >= k && max < facter[i]) {
        max = facter[i];
        ans = i;
    }
    cout << ans << endl;
}