n = int(input())

if n == 1:
  print(0)
  exit()

if n & 1 :
  n -= 1
  cnt = 1
else :
  cnt = 0
while n != 0:
  n, m = divmod(n, 2)
  cnt += 1
  if n == 1 and m == 0:
    break

print(cnt)