#include <iostream>
#include <cmath>
using namespace std;

int main() {
    long long N;
    cin >> N;

    long long sum = 0;

    for (long long i = 1; i <= sqrt(N); i++) {
        if (N % i == 0) {
            sum += i; 
            if (i != N / i) {
                sum += N / i; 
            }
        }
    }

    cout << sum << endl;
    return 0;
}