#include <bits/stdc++.h>
using namespace std;
int n, k, a, b, j;

int zjy(int u) {
	for (int i = 2; i <= u / 2; ++i) {
		if (n % i == 0) {
			k += i;
			j++;
			k += zjy(u / i);
		}
	}
	return k;
}

void dfs(int y) {
	if (y > n) {
		return ;
	}
	if (a % zjy(y) == 0) {
		b++;
	}
	dfs(y + 1);
}

int main() {
	freopen("fx.in", "r", stdin)
	freopen("fx.out", "w", stdout)
	cin >> n;
	a = zjy(n);
	dfs(1);
	cout << k;
	return 0;
}