#include <cassert>
#include <cmath>
#include <iostream>
#include <tuple>
#include <queue>
#include <vector>
using namespace std;
using i64 = int64_t;

vector<int> factorize(int n) {
  vector<int> v(n+1);
  for(int d=2; d*d<=n; ++d) {
    while(n % d == 0) {
      ++v[d];
      n /= d;
    }
  }
  if(n > 1) { ++v[n]; }
  return v;
}

template <class Int>
vector<Int> sieve(Int n) {
  vector<bool> is_prime(n+1, true);
  is_prime[0] = is_prime[1] = false;
  Int sq = Int(sqrt(n));
  for(Int i=2; i<=sq; ++i) {
    if(is_prime[i]) {
      for(Int j=i*i; j<=n; j+=i) {
        is_prime[j] = false;
      }
    }
  }
  vector<Int> res;
  for(Int i=2; i<=n; ++i) {
    if(is_prime[i]) {
      res.push_back(i);
    }
  }
  return res;
}

void debug(const vector<int> &vec_) {
  for(size_t i=0, n=vec_.size(); i<n; ++i) {
    if(i) { fprintf(stderr, " "); }
    fprintf(stderr, "%d", vec_[i]);
  }
  fprintf(stderr, "\n");
}

i64 f(int x, int K) {
  constexpr int inf = 987'654'321;
  vector<int> primes = sieve(x);
  int n = static_cast<int>(primes.size());
  vector<int> fac = factorize(x);
  // 約数の個数(dcnt), 共通の素因数の個数(ccnt), i番目の素数, k個使う, 値
  queue<tuple<int, int, int, int, i64>> que;
  que.emplace(1, 0, 0, 0, 1);
  i64 res = inf;
  int max_dcnt = 0;
  while(!que.empty()) {
    int dcnt, ccnt, i, k; i64 val; tie(dcnt, ccnt, i, k, val) = que.front(); que.pop();
    if(val >= x) { continue; }
    if(ccnt >= K) {
      if(max_dcnt < dcnt) {
        max_dcnt = dcnt;
        res = val;
      } else if(max_dcnt == dcnt) {
        res = min(res, val);
      }
    }
    // i番目をk個からk+1個にする
    int p = primes[i];
    bool have = fac[p] >= k+1;
    que.emplace(dcnt*(k+2)/(k+1), ccnt+have, i, k+1, val*p);
    // j番目をはじめて使う
    for(int j=i+1; j<n && val*primes[j]<x; ++j) {
      p = primes[j];
      have = fac[p] >= 1;
      que.emplace(dcnt*2, ccnt+have, j, 1, val*p);
    }
  }
  return res;
}

int main(void) {
  int N, K; scanf("%d%d", &N, &K);
  i64 res = f(N, K);
  printf("%ld\n", res);
  return 0;
}