#include <iostream>
#include <cstdio>
#include <cmath>
using namespace std;
long long a;
int su[10000000]={0};
int shu(int q)
{
	int w,e,r;
	for (w=2;w<=a;w++)
	{
		r=0;
		for (e=1;e<=pow(double(w),0.5);e++)
		{
			if(w%e==0)
			{
				r++;
			}
		}
		if(r==1)
		{
			su[w]=1;
		}
	}
}
int main(){
	freopen ("prime.in","r",stdin);
	freopen ("prime.out","w",stdout);
	int b,c,d,e,f;
	cin>>a;
	shu(a);
	b=0;
	d=a;
	for (e=1;e<=pow(double(a),0.5);e++)
	{
		if(su[e]==1)
		{
			if(a%e==0&&e>b&&su[a/e]==1)
			{
				b=a/e;
			}
		}
	}
	cout<<b;
	return 0;
}