import math

def main():
    N = int(input())

    if N == 1:
        print(0)
        return
    n = math.log2(N)
    if not n % 1:
        print(int(n))
    else:
        n = int(n + 1)
        x = 2 ** n
        while x > N:
            x -= 1
            n += 1
        print(n)

main()