#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <cmath>
using namespace std;
using ll = long long;

int main() {
    ll n;
    cin >> n;

    ll s = 0;
    for (ll i = 1; i * i <= n; i++) {
        if (n % i == 0) {
            if (i * i < n) s += n / i;
            s += i;
        }
    }

    cout << s << endl;

    return 0;
}