#include<iostream>
#include<algorithm>
using namespace std;
using lint=int64_t;

int main()
{
	lint N;
	lint ans=0;

	cin >> N;

	for(lint i=1;i*i<=N;i++)
	{
		if(N%i==0)
		{
			ans+=(i+N/i);
			if(i==N/i)
				ans-=i;
		}
	}

	cout << ans << endl;
	return 0;
}