#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("Yes");}else{puts("No");}
#define MAX_N 200005

vector<ll> yakusuu_rekkyo(ll n){
    vector<ll> divisors;
    for(ll i = 1; i <= n; i++){
        if(i * i > n)break;
        if(i * i == n){
            divisors.push_back(i);
            break;
        }else if(n % i == 0){
            divisors.push_back(i);
            divisors.push_back(n/i);
        }   
    }
    sort(divisors.begin(), divisors.end());
    return divisors;
}

vector<pair<ll, int>> fac;
void PrimeFactorInit(ll x){ // 素因数と個数のペアを返す.
    fac.clear();
    if(x >= 2){
        for(ll i = 2; i <= x; i++){
            if(i * i > x)break;
            if(x % i == 0){
                int cnt = 0;
                while(x % i == 0){
                    cnt++;
                    x /= i;
                }
                pair<ll, int> p;
                p.first = i;
                p.second = cnt;
                fac.push_back(p);
            }
        }
        if(x > 1){
            pair<ll, int> p;
            p.first = x;
            p.second = 1;
            fac.push_back(p);
        }
    }
}

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

    PrimeFactorInit(n);
    int f[n+1] = {};
    rep(i,fac.size()){
        f[fac[i].first] = fac[i].second;
    }

    int ma = 0;
    int ans = 0;
    srep(i,1,n){
        PrimeFactorInit(i);
        int cnt = 0;
        rep(j,fac.size()){
            cnt += min(f[fac[i].first],fac[i].second);
        }
        if(cnt>=K){
            vector<ll> v = yakusuu_rekkyo(i);
            if(v.size() > ma){
                ma = v.size();
                ans = i;
            }
        }
    }

    cout << ans << endl;
}