#include<iostream>
#include<set>
#include<algorithm>
#include<vector>
#include<string>
#include<set>
#include<map>
#include<numeric>
#include<queue>
#include<cmath>
using namespace std;
typedef long long ll;
const ll INF=1LL<<60;
typedef pair<int,int> P;
typedef pair<int,P> PP;
const ll MOD=1e9+7;

vector<pair<ll,ll>> primediv(ll n){
    vector<pair<ll,ll>> res;
 
    for(ll p=2;p*p<=n;p++){
        if(n%p==0){
            pair<ll,ll> tmp;

            tmp.first=p,tmp.second=0;
            while(n%p==0){
                n/=p;
                tmp.second++;
            }
            res.push_back(tmp);
        }
    }

    if(n>1){
        res.emplace_back(n,1);
    }

    return res;
}


int main(){
    int N,K;
    cin>>N>>K;

    auto primenum=primediv(N);


    ll maxnum=0;//約数の個数のmax
    ll ans=0;

    for(int i=1;i<N;i++){
        //cout<<"i="<<i<<endl;

        ll cntnum=1;

        
        ll k=0;
        ll tmpi=i;
        for(auto [v,num]:primenum){
            if(tmpi%v==0){
                
                ll t=0;
                while(tmpi%v==0){
                    t++;
                    tmpi/=v;
                }

                k+=min(t,num);
            }
        }

        if(k>=K){
            
            ll candnum=1;
            ll cand=i;
            for(ll d=2;d*d<=i;d++){
                
                if(cand%d==0){
                    ll t=0;

                    while(cand%d==0){
                        t++;
                        cand/=d;
                    }

                    candnum*=(t+1);
                }
            }
            if(maxnum<candnum){

                ans=i;
                maxnum=candnum;

            }
            //cout<<"ans="<<ans<<endl;
            //cout<<"maxnum="<<maxnum<<endl;
        }
    }

    cout<<ans<<endl;

}