#include <iostream>
typedef long long ll;
using namespace std;

int main() {
    ll N;
    cin >> N;
    ll sum = 0;
    for (ll i = 1; i * i <= N; i++) {
        if (N % i == 0) {
            sum += i;
            if (i * i != N) sum += N / i;
        }
    }
    cout << sum << endl;
    return 0;
}