#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> l_l;
typedef pair<int, int> i_i;

#define EPS (1e-7)
#define INF (1e9)
#define PI (acos(-1))
//const ll mod = 1000000007;
vector<int> primes;
int factor[100050];

int main() {
    //cout.precision(10);
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N, K;
    cin >> N >> K;
    for(int i = 2; i <= 1000; i++) {
        bool ok = true;
        for(int j = 2; j * j <= i; j++) {
            if(i % j == 0) ok = false;
        }
        if(ok) primes.push_back(i);
    }
    int copy = N;
    for(int i = 2; i <= 1000; i++) {
        while(copy % i == 0) {
            factor[i]++;
            copy /= i;
        }
    }
    if(copy > 1) factor[copy]++;
    int ans = 1;
    int val = 0;
    for(int i = 2; i < N; i++) {
        copy = i;
        int now_val = 1;
        int now_k = 0;
        for(int j = 0; j < primes.size(); j++) {
            int p = primes[j];
            if(p * p > copy) break;
            int now_factor = 0;
            while(copy % p == 0) {
                copy /= p;
                now_factor++;
            }
            now_k += min(now_factor, factor[p]);
            now_val *= (now_factor + 1);
        }
        if(copy > 1) {
            now_k += min(1, factor[copy]);
            now_val *= 2;
        }
        if(now_k < K) continue;
        if(now_val > val) {
            ans = i;
            val = now_val;
        }
    }
    cout << ans << endl;
    return 0;
}