#include "bits/stdc++.h"
using namespace std;
#define print(x) cout<<x<<endl;
#define rep(i,a,b) for(int i=a;i<b;i++)
#define REP(i,a) for(int i=0;i<a;i++)
typedef long long ll;
typedef pair<int, int> PI;
typedef pair<int, PI> V;
typedef vector<int> VE;
const ll mod = 1000000007;

int is_prime(ll n){
  for(ll i=3;i*i<=n;i++){
    if(n%i==0)return i;
  }
  return 0;
}

int main() {
  ll n;
  cin>>n;
  ll ans=is_prime(n);
  if(ans){
    print(ans);
  }
  else {
    if(n%2==0&&n/2!=2){print(n/2);}
    else{
      print(n);
    }
  }
}