#include<iostream>
using namespace std;
int main()
{
	int s,div=1;
	double n;
	cin>>n;
	while(div<=sqrt(n))
	{
		if(fmod(n,div)==0)
		{
			if(n/div==div)
				s=s+div;
			else
				s=s+(n/div)+div;
		}
		div=div+1;
	}
	cout<<s;
	return 1;
}