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

    return 0;
}
/**************************************************************
	Problem: 1084
	User: mariooo
	Language: C++
	Result: Wrong Answer
****************************************************************/