import sys

def check_range(a,b,x):
	if a > x or b < x:
		sys.exit()

def check_eq(a,b):
	if a != b:
		sys.exit()

def cal(x):
	if x == 1:
		return 0

	elif x == 2:
		return 1

	elif x // 2 == 1:
		return cal(x // 2) + 2
	
	else:
		return cal(x // 2) + 1 		

N = int(input())
check_range(1,100000000,N)

print(cal(N))