#include <iostream>
using namespace std;

int main() {
	long N, ans = 0;
	cin >> N;
	for (long i = 1; i * i <= N; ++i) {
		if (0 == N % i) {
			ans += N / i;
			if (N / i != i) ans += i;
		}
	}
	cout << ans;
}