#include <iostream>
#include <cmath>
using namespace std;
int main(void) {
	long long n;
	cin >> n;
	long long ans = 0;
	for (int i = 1; i <= sqrt(n); ++i) {
		if (n % i == 0)
			ans += i,
			ans += n / i;
	}
	cout << ans << endl;
	return 0;
}