object Main {
	
	def countBinNumDigits(num:Long) = {
		assert (num >= 0L)

		@scala.annotation.tailrec
		def loop (num:Long) (result:Int) :Int = {
			if (num == 0L) result
			else {
				val (nextNum, nextResult) =
					(num >> 1, result + 1)
				loop (nextNum) (nextResult)
			}
		}
		loop (num) (0)
	}

	def countHit(num:Long) = {
		assert (num > 0L)
		
		val cntHit = countBinNumDigits(num) - 1
		val rem = num - (1L << cntHit)
		
		if (rem == 0) cntHit
		else cntHit + 1
	}
	
	def main(args: Array[String]): Unit = {
		val num = readLine().toLong
		val ans = countHit(num)
		println(ans)
	}
}