#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<int, int>;
using T = tuple<int, int, int>;
#define al(a) a.begin(), a.end()
#define ral(a) a.rbegin(), a.rend()
#define sz(a) (int)a.size()
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rrep(i, n) for (int i = 1; i <= (n); ++i)
#define drep(i, n) for (int i = (n)-1; i >= 0; --i)
#define db(a, b) cout << #a << ": " << a << " " << #b << ": " << b << endl;

int main() {
  ll n;
  cin >> n;

  vector<ll> div;
  for (ll i = 1; i * i <= n; ++i) {
    if (n % i) continue;
    div.push_back(i);
    if (n / i != i) div.push_back(n / i);
  }
  sort(al(div));
  for (auto d : div) {
    if (d > 2) {
      cout << d << endl;
      return 0;
    }
  }
}

// int main() {
//   ll n;
//   cin >> n;

//   for (ll i = 3; i * i <= n; ++i) {
//     if (n % i == 0) {
//       cout << i << endl;
//       return 0;
//     }
//   }
//   if (n % 2 == 0 && n / 2 > 2) n /= 2;
//   cout << n << endl;
//   return 0;
// }