#include<bits/stdc++.h>
using namespace std;
int main()
{
    int n;
    int cnt = 0;
    cin>>n;
    for(int i=2;i<=n-1;i++)
    {
        if(n%i==0)
        {
            cnt+=i;
        }
    }
    cout<<cnt;
    return 0;
}
/**************************************************************
	Problem: 1084
	User: wuyichen
	Language: C++
	Result: Time Limit Exceed
****************************************************************/