#include<iostream>
#include<algorithm>
#include<string>

using namespace std;

long long n;
int f;

int main(){
	cin>>n;
	if(n==6){
		cout<<3<<endl;
		f=1;
	}
	if(n==8){
		cout<<4<<endl;
		f=1;
	}
	for(long long i=3;i*i<=n;i++){
		if(n%i==0){
			cout<<i<<endl;
			f=1;
			break;
		}
	}
	if(f==0){
		if(n%2==0&&n!=4) cout<<n/2<<endl;
		else{
		cout<<n<<endl;
		}
	}
	return 0;
}