import math


def log2ceil(x):
    """
    Returns no of bits required to store x-1
    for example x=8 returns 3
    """

    if not isinstance(x, (int, float)):
        x = int(x)

    if x == 0 or x == 1:
        res = 1
    else:
        res = math.ceil(math.log2(x))

    return res