#include <bits/stdc++.h>
#define PI 3.14159265359
using namespace std;
const int64_t MOD = 1e9 + 7;

int main() {
	int64_t N;
	cin >> N;

	int64_t sum = 0;
	for (int64_t i = 1; i <= N; i++) {
		if (N % i == 0) {
			sum += i;
		}
	}

	cout << sum << endl;
}