#include<bits/stdc++.h>
using namespace std;
#define ALL(x) x.begin(),x.end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define debug(v) cout<<#v<<":";for(auto x:v){cout<<x<<' ';}cout<<endl;
#define INF 1000000000
#define mod 1000000007
using ll=long long;
const ll LINF=1001002003004005006ll;
int dx[]={1,0,-1,0};
int dy[]={0,1,0,-1};
// ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return true;}return false;}

map<ll, int> PrimeFactor(ll n){
    map<ll,int> ret;
    for(ll i=2;i*i<=n;i++){
        while(n%i==0){
            ret[i]++;
            n/=i;
        }
    }
    if(n!=1) ret[n]=1;
    return ret;
}

signed main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    ll n,k;cin>>n>>k;
    auto pfn=PrimeFactor(n);
    ll ans,cnt=0;
    for(ll i=1;i<n;i++){
        auto mp=PrimeFactor(i);
        ll t=0;
        for(auto p:mp){
            if(pfn.count(p.first)) t+=min(p.second,pfn[p.first]);
        }
        if(t>=k){
            ll x=1;
            for(auto p:mp) x*=(p.second+1ll);
            if(chmax(cnt,x)) ans=i;
        }
    }
    cout<<ans<<endl;
    return 0;
}