#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,p=0;
	cin>>n;
	for(int i=2;i<=n-1;i++){
		if(n%i==0){
			p=p+i;
		}	
	}
	cout<<p;

	return 0;
}
/**************************************************************
	Problem: 1084
	User: wuzihang
	Language: C++
	Result: Time Limit Exceed
****************************************************************/