goal_number = int(input())
hit = 0
bisckt_number = 1
while bisckt_number <= goal_number:
	hit += 1
	bisckt_number = bisckt_number*2
if bisckt_number/2 == goal_number:
	print(hit - 1)
elif bisckt_number/2 < goal_number:
	print(hit)
else:
	print(error)