#include <bits/stdc++.h>
using namespace std;

vector<long> div(long n) {
  vector<long> v;
  for (long i = 1; i * i <= n; i++) {
    if (n % i == 0) {
      v.push_back(i);
      if (i * i != n) v.push_back(n / i);
    }
  }
  sort(begin(v), end(v));
  return v;
}

int main() {
  long N;
  cin >> N;
  vector<long> V = div(N);
  for (auto a : V) if (a > 2) return cout << a << "\n", 0;
}