#include<bits/stdc++.h>
using namespace std;
int main()
{
	int n,s=0;
	cin>>n;
	for(int i=2;i<n;i++){
		if(n%i==0){
			s+=i;
		}
	}
	cout<<s;
	return 0;
}

/**************************************************************
	Problem: 1084
	User: zzz
	Language: C++
	Result: Time Limit Exceed
****************************************************************/