#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <chrono>
#define _USE_MATH_DEFINES
#include <cmath>
#include <cstdio>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iostream>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <string>
#include <tuple>
#include <utility>
#include <vector>
using namespace std;

#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()

const int INF = 0x3f3f3f3f;
const long long LINF = 0x3f3f3f3f3f3f3f3fLL;
const double EPS = 1e-8;
const int MOD = 1000000007; // 998244353;
const int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1};
/*-------------------------------------------------*/
vector<pair<long long, int> > prime_factorization(long long num) {
  vector<pair<long long, int> > res;
  for (long long i = 2; i * i <= num; ++i) {
    if (num % i != 0) continue;
    int exponent = 0;
    while (num % i == 0) {
      ++exponent;
      num /= i;
    }
    res.emplace_back(i, exponent);
  }
  if (num != 1) res.emplace_back(num, 1);
  return res;
}

int main() {
  cin.tie(0); ios::sync_with_stdio(false);
  // freopen("input.txt", "r", stdin);

  int n, k; cin >> n >> k;
  auto prime = prime_factorization(n);
  map<long long, int> mp;
  for (auto p : prime) mp[p.first] = p.second;
  int ans = 1, yakusu = 0;
  FOR(i, 2, n) {
    auto tmp = prime_factorization(i);
    int cnt = 0;
    for (auto p : tmp) {
      if (mp.count(p.first) > 0) cnt += min(p.second, mp[p.first]);
    }
    if (cnt >= k) {
      long long kosu = 1;
      for (auto p : tmp) kosu *= p.second + 1;
      if (kosu > yakusu) {
        ans = i;
        yakusu = kosu;
      }
    }
  }
  cout << ans << '\n';
  return 0;
}