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

vector<int64_t> sieve(int64_t n){
    vector<int64_t> ret;
    vector<bool> is_prime(n+1);
    for(int64_t i=2; i<=n; i++) is_prime[i] = true;
    for(int64_t i=2; i<=n; i++){
        if(is_prime[i]){
            ret.push_back(i);
            for(int64_t j=2*i; j<=n; j+=i) is_prime[j] = false;
        }
    }
    return ret;
}

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

    auto primes = sieve(100000);
    map<int, int> pn;
    int num = N;
    for(int64_t p : primes){
        if(p*p > num) break;
        while(num % p == 0){
            pn[p]++;
            num /= p;
        }
    }
    if(num > 1) pn[num]++;

    int mx = 0;
    int ans;
    for(int i=1; i<N; i++){
        map<int, int> pi;
        int num = i;
        for(int64_t p : primes){
            if(p*p > num) break;
            while(num % p == 0){
                pi[p]++;
                num /= p;
            }
        }
        if(num > 1) pi[num]++;

        int k = 0;
        for(auto& p : pn){
            k += min(p.second, pi[p.first]);
        }
        if(k < K) continue;
        int result = 1;
        for(auto& p : pi) result *= 1+p.second;
        if(mx < result){
            mx = result;
            ans = i;
        }
    }
    cout << ans << endl;
    return 0;
}