#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <functional>
#include <algorithm>
#include <string>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
using namespace std;
template<class T, class Compare = less<T> >
using MaxHeap = priority_queue<T, vector<T>, Compare>;
template<class T, class Compare = greater<T> >
using MinHeap = priority_queue<T, vector<T>, Compare>;
using llong = long long;

llong n;
llong ans;

int main() {
    cin >> n;

    for (llong i = 1; i * i <= n; i++) {
        if (n % i == 0) {
            ans += i;
        }
        if (n % i == 0 && n / i != i) {
            ans += n / i;
        }
    }

    cout << ans << endl;

    return 0;
}