def primefactor(n):
	res = []
	i = 2
	while i * i <= n:
		num = 0
		while n % i == 0:
			num += 1
			n /= i
		if num > 0: res.append((i, num))
		i += 1
	if n != 1: res.append((n, 1))
	return res

N = input()
fac = []
if N % 2 == 0:
	fac = primefactor(N / 2)
else:
	fac = primefactor(N)
ans = 1
for p, e in fac:
	ans *= (p ** (e + 1) - 1) / (p - 1)
print ans