#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pb push_back
#define fi first
#define se second
#define rep(i,s,n) for(int i = s;i<n;i++)
#define rrep(i,s,n) for(int i = (n)-1;i>=(s);i--)
#define all(v) (v).begin(),(v).end()
#define chmin(a,b) a=min((a),(b))
#define chmax(a,b) a=max((a),(b))
#define endl '\n'
#define IOS() ios_base::sync_with_stdio(0);cin.tie(0)
typedef long long ll;
typedef pair<int,int>pint;
typedef vector<int>vint;
typedef vector<pint>vpint;
const ll MOD=1000000007,INF=1e18;
int dx[]={0,0,1,-1},dy[]={-1,1,0,0};
typedef pair<int,pint>P2;

int N,K;

vector<pair<long long, long long> > prime_factorize(long long n) {
    vector<pair<long long, long long> > res;
    for (long long p = 2; p * p <= n; ++p) {
        if (n % p != 0) continue;
        int num = 0;
        while (n % p == 0) { ++num; n /= p; }
        res.push_back(make_pair(p, num));
    }
    if (n != 1) res.push_back(make_pair(n, 1));
    return res;
}

signed main() {
    IOS();
    cin>>N>>K;
    auto v=prime_factorize(N);
    vint cnt(100010,0);
    for(auto e:v)cnt[e.fi]=e.se;
    
    int ans=0,id;
    rep(i,1,N){
        auto tmp=prime_factorize(i);
        int t=0,sum=1;
        for(auto e:tmp){
            sum*=e.se+1;
            t+=min(e.se,cnt[e.fi]);
        }
        if(t>=K){
            if(ans<sum){
                ans=sum;
                id=i;
            }
        }
    }
    cout<<id<<endl;
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    return 0;
}