#include <bits/stdc++.h>
using namespace std;
int main(){
	int i,sum=0;
	cin>>i;
	for(int i2=2;i2<i;i2++){
		if(i%i2==0)sum+=i2;
	}
	cout<<sum;
	return 0;
}

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