N=gets.chomp.to_i

def nishinsuu(num)
  keta = 1
  total = 0
  while num > 0
    num = num >> 1
    keta += 1
  end
  saidaiketa = keta - 1
  amari = num % (2 ** saidaiketa)
  return (saidaiketa - 1) + amari
end

puts nishinsuu(N)