def is_perfect_square(n):
i = 1
while i * i < n:
i += 1
return i * i == n, i
def aliquot(n):
sum = 1
i = 2
is_ps, root = is_perfect_square(n)
while i < root:
if n % i == 0:
sum += i + (n / i)
i += 1
return sum
n = int(raw_input('Enter a number? '))
print aliquot(n)