#include <bits/stdc++.h>

using namespace std;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int64_t N;
  cin >> N;
  vector<int64_t> cands = {N};
  for (int64_t i = 2; i * i < N + 1; i++) {
    if (N % i == 0) {
      if (i != 2) cands.emplace_back(i);
      if (N / i != 2) cands.emplace_back(N / i);
    }
  }
  sort(cands.begin(), cands.end());
  cout << cands.front() << '\n';
  return 0;
}