#include<bits/stdc++.h>
using namespace std;
using ll = long long;

#define FOR(i,a,b) for(ll i=(a);i<(b);++i)
#define ALL(v) (v).begin(), (v).end()
#define p(s) cout<<(s)<<endl
#define p2(s, t) cout << (s) << " " << (t) << endl
#define br() p("")
#define pn(s) cout << (#s) << " " << (s) << endl
#define p_yes() p("Yes")
#define p_no() p("No")

const ll mod = 1e9 + 7;
const ll inf = 1e18;

ll gcd(ll a,ll b){
    if(b == 0) return a;
    return gcd(b,a%b);
}

map<ll, ll> factorize(ll n){
    map<ll, ll> mp;
    ll sq = sqrt(n);
    FOR(i, 2, sq+1){
        while(n%i==0){
            mp[i]++;
            n/=i;
        }
    }
    // 残り
    if(n!=1){
        mp[n]++;
    }
    return mp;
}

// 素因数の個数 (重複あり) ex. {2, 2, 2, 3}
ll prime_factor_num(ll a){
    ll count = 0;
    auto mp = factorize(a);
    for(auto p : mp){
        count += p.second;
    }
    return count;
}

// a, bの共通の素因数の数
ll common(ll a, ll b){
    ll g = gcd(a, b);
    return prime_factor_num(g);
}

// 約数の個数
ll divisor_num(ll a){
    auto mp = factorize(a);
    ll ret = 1;
    for(auto p : mp){
        ret *= (p.second + 1);
    }
    return ret;
}

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

    // input
    ll N, K;
    cin >> N >> K;

    ll max_divisor_num = 0;
    ll max_M;
    FOR(i, 1, N){
        if(common(i, N)>=K){
            ll div = divisor_num(i);
            if(div > max_divisor_num){
                max_divisor_num = div;
                max_M = i;
            }
        }
    }

    p(max_M);
    
    return 0;
}