N = gets.to_i

sum = (1 + (N - 1)) * (N - 1) / 2

ans = 0

1.upto(Math.sqrt(N).floor) {|i|
  if N % i == 0 and sum % i == 0
    ans += i
    ans += (N / i) if sum % (N / i) == 0 and (N / i) ** 2 != 0
  end
}

puts ans