#include<bits/stdc++.h>
using namespace std;
int main()
{
	int n,s=0;
	cin>>n;
	for(int i=2;i<=sqrt(n);i++){
		if(n%i==0){
			s=s+i+n/i;
			if(n/i==i){
				s-=i;
			}
		}
	}
	cout<<s;
	return 0;
}
/**************************************************************
	Problem: 1086
	User: zzz
	Language: C++
	Result: Wrong Answer
****************************************************************/