def divisor(number):
  lower_divisors ,upper_divisors = [], []
  i = 1
  
  while i**2 <= number:
    if number % i == 0:
      lower_divisors.append(i)
      if i != number // i:
        upper_divisors.append(number//i)
    i += 1
  
  return lower_divisors + upper_divisors[::-1]

N = int(input().strip())

print(sum(divisor(N)))