first = input()
chalks = [int(first)]
breakTimes = 0
while True:
    chalk = chalks.pop(0)
    if chalk < 1:
        pass
    else:
        x = (chalk-1)/2
        chalk = chalk-x-1
        chalks.append(chalk)
        chalks.append(x)
        breakTimes+=1
    if chalks == []:
        break
print(breakTimes)
print("")