#include<bits/stdc++.h>
using namespace std;
int main()
{
    int n;
	cin>>n;
	int a=0;
	int s=0;
	for(int i=2;i<=sqrt(n);i++)
	{
		if(n%i==0)
		{
			s+=i;
			if(n/i!=i)
			{
				s+=n/i;	
			}
		}
	}
	cout<<s;	
	return 0;
}
/**************************************************************
	Problem: 1084
	User: chenkexin
	Language: C++
	Result: Accepted
	Time:15 ms
	Memory:2072 kb
****************************************************************/