#include <bits/stdc++.h>

using namespace std;
using ll = long long;
// #define int ll
using PII = pair<ll, ll>;

#define FOR(i, a, n) for (ll i = (ll)a; i < (ll)n; ++i)
#define REP(i, n) FOR(i, 0, n)
#define ALL(x) x.begin(), x.end()

template<typename T> T &chmin(T &a, const T &b) { return a = min(a, b); }
template<typename T> T &chmax(T &a, const T &b) { return a = max(a, b); }
template<typename T> bool IN(T a, T b, T x) { return a<=x&&x<b; }
template<typename T> T ceil(T a, T b) { return a/b + !!(a%b); }

template<typename T> vector<T> make_v(size_t a) { return vector<T>(a); }
template<typename T,typename... Ts>
auto make_v(size_t a,Ts... ts) { 
    return vector<decltype(make_v<T>(ts...))>(a,make_v<T>(ts...));
}
template<typename T,typename V> typename enable_if<is_class<T>::value==0>::type
fill_v(T &t, const V &v) { t=v; }
template<typename T,typename V> typename enable_if<is_class<T>::value!=0>::type
fill_v(T &t, const V &v ) { for(auto &e:t) fill_v(e,v); }

template<class S,class T>
ostream &operator <<(ostream& out,const pair<S,T>& a){
    out<<'('<<a.first<<','<<a.second<<')'; return out;
}
template<class T>
ostream &operator <<(ostream& out,const vector<T>& a){
    out<<'['; for(T i: a) {out<<i<<',';} out<<']'; return out;
}

int dx[] = {0, 1, 0, -1}, dy[] = {1, 0, -1, 0}; // DRUL
const int INF = 1<<30;
const ll LLINF = 1LL<<60;
const ll MOD = 1000000007;

signed main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    ll n, k;
    cin >> n >> k;

    ll t = n;
    vector<ll> mp(n+1);
    for(ll i=2; i*i<=t; ++i) {
        while(t%i==0) t/=i, mp[i]++;
    }
    if(t>1) mp[t]++;

    ll ma = 0, ans = 0;
    FOR(i, 1, n) {
        // iとnの共通素因数
        ll num = 0;
        t = i;
        for(ll j=2; j*j<=t; ++j) {
            ll cnt = 0;
            while(t%j==0) t/=j, cnt++;
            num += min(cnt, mp[j]);
        }
        if(t>1) num += min(1LL, mp[t]);
        if(num < k) continue;
        // iの約数
        t = i, num = 0;
        for(ll j=1; j*j<=i; ++j) {
            if(t%j==0) {
                num++;
                if(j*j != i) num++;
            }
        }
        if(num > ma || (num == ma && ans > i)) {
            ma = num;
            ans = i;
        }
    }
    cout << ans << endl;

    return 0;
}