#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<ll> VL;
typedef vector<VL> VVL;
typedef pair<int, int> PII;

#define FOR(i, a, n) for (ll i = (ll)a; i < (ll)n; ++i)
#define REP(i, n) FOR(i, 0, n)
#define ALL(x) x.begin(), x.end()
#define MOD 1000000007
#define INF (1LL<<25)     //33554432
#define PI 3.14159265359
#define EPS 1e-12
//#define int ll

signed main(void)
{
  ll n;
  cin >> n;

  VL v;
  for(ll i=1; i*i<=n; ++i) {
    //cout << i << " " << n%i << endl;
    if(n%i == 0) {
      //cout << "a" << endl;
      v.push_back(i);
      if(i*i != n) v.push_back(n/i);
    }
  }

  sort(ALL(v));
  for(ll i: v) {
    //cout << i << endl;
    if(i >= 3) {
      cout << i << endl;
      break;
    }
  }

  return 0;
}