#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> lpair;
const ll MOD = 1e9 + 7;
const ll INF = 1e18;
#define rep(i,m,n) for(ll i = (m); i < (n); i++)
#define rrep(i,m,n) for(ll i = (m); i >= (n); i--)
#define print(x) cout << (x) << endl;
#define print2(x,y) cout << (x) << " " << (y) << endl;
#define printa(x,n) for(ll i = 0; i < n; i++){ cout << (x[i]) << " ";} cout<<endl;

inline vector<ll> factor(ll M){ //素因数分解
    vector<ll> dd;
    if(M == 1){
        dd.push_back(1);
        return dd;
    }
    for(ll i = 2; i*i <= M; i++){
        while(M % i == 0){
            dd.push_back(i);
            M /= i;
        }
    }
    if(M != 1) dd.push_back(M);
    sort(dd.begin(), dd.end());
    return dd;
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    ll N,K;
    cin >> N >> K;
    vector<ll> dd = factor(N);
    ll nn = dd.size();
    map<ll,ll> mp;
    rep(i,0,nn) mp[dd[i]]++;
    ll ans = 0, max_val = 0;
    rep(t,1,N){
        vector<ll> tt = factor(t);
        map<ll,ll> mp2;
        rep(i,0,tt.size()) mp2[tt[i]]++;
        ll k = 0;
        for(auto &e: mp2){
            k += min(e.second, mp[e.first]);
        }
        if(k < K) continue;
        ll v = 1;
        for(auto &e: mp2){
            v *= e.second + 1;
        }
        if(max_val < v){
            max_val = v;
            ans = t;
        }
    }
    print(ans);




}