#define _GLIBCXX_DEBUG
#define ll long long
#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

int main(){
  ll N; cin >> N;
  map<ll, int> mp;
  for(ll i = 1; i*i <= N; i++){
    if(N%i == 0){
      mp[N/i]++;
      mp[i]++;
    }
  }
  for(auto p: mp){
    if(p.first >= 3){
      cout << p.first << endl;
      return 0;
    }
  }
}