#include<iostream>
#include<vector>
#include<string>
#include<cmath>
#include<algorithm>
#include<functional>
#include<numeric>
#include<queue>
#include<stack>
#include<map>
#include<unordered_map>
#include<set>
#include<bitset>
#include<random>

#pragma region
using namespace std;
#define FOR(i,r,n) for(ll i = (ll)(r); i < (ll)(n); i++)
#define rep(i,n) FOR(i,0LL,n)
#define RFOR(i,r,n) for(ll i=(ll)(n-1);i>=r;i--)
#define rrep(i,n) RFOR(i,0LL,n)
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define COUNT(a,y,x) upper_bound(all(a), y) - lower_bound(all(a), x)
#define UNIQUE(a) sort(all(a)); a.erase(unique(all(a)), a.end())
#define pb push_back
typedef long long int ll;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef pair<ll, ll> pll;
typedef vector<pll> vpll;
typedef vector<string> vs;
typedef map<ll, ll> MAP;
const ll inf = 2222222222222222222LL;
const ll mod = 1000000007LL;

ll n = 0, m = 0, ans = 0, tmp = 0, ma = -inf, mi = inf;
string s;
bool ok;
ll dx[9] = { 0,1,-1,0,0,1,1,-1,-1 }, dy[9] = { 0,0,0,1,-1,1,-1,1,-1 };
#define endl '\n'
#pragma endregion
#define MAX 222222


ll num1[MAX], num[MAX];

MAP factor(ll x) {
  MAP ret;
  for (ll i = 2; i*i <= x; i++) {
    while (x%i == 0) {
      ret[i]++;
      x /= i;
    }
  }
  if (x != 1)ret[x]++;
  return ret;
}

vll pr;
bool is[MAX + 1];

void AllPrime(ll x) {
  rep(i, x + 1) is[i] = true;
  is[0] = false;
  is[1] = false;
  rep(i, x + 1) {
    if (is[i]) {
      pr.pb(i);
      for (ll j = 2 * i; j <= x; j += i) is[j] = false;
    }
  }
}


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



  cin >> n >> m;
  AllPrime(n + 1);
  rep(i,n+1) num[i]=1;
  rep(i, pr.size()) {
    ll cur = pr[i];
    rep(j, n + 1) num1[j] = 0;
    while (cur <= n) {
      for (ll j = cur; j <= n; j += cur) {
        num1[j]++;
      }
      cur *= pr[i];
    }
    rep(j, n + 1) if (num1[j]) num[j] *= num1[j] + 1;
  }
  MAP mp = factor(n);
  vpll fac;
  for (auto it : mp) {
    fac.pb(make_pair(it.first, it.second));
  }

  RFOR(i, 1, n) {
    if (ma > num[i]) continue;
    ll cnt = 0, cur = i;
    rep(i, fac.size()) {
      rep(j, fac[i].second) {
        if (cur%fac[i].first == 0) {
          cur /= fac[i].first;
          cnt++;
        }
        else break;
      }
    }
    if (cnt < m) continue;
    ma = num[i];
    ans = i;
  }

  cout << ans << endl;
  

  return 0;
}