#include <bits/stdc++.h>
using namespace std;

int main()
{
    long n, s = 0;
    cin >> n;
    for (long i = 1; i * i <= n; i++) {
        if (n % i == 0) {
            s += i + n / i;
        }
        if (i * i == n) {
            s -= i;
        }
    }
    cout << s << endl;
}