num = input()
num = int(num)
kekka = 1
count = 0
tmp = 0
while kekka*2 <= num:
    kekka *= 2
    if tmp == 0 and kekka >= num/2 and kekka != num:
        tmp = (kekka - num/2)*2
        kekka -= tmp
    count += 1
kekka += tmp
print(count)