import math


def circle_length(r: int):
    if r <= 0:
        raise Exception("radius cannot be negative")
    else:
        c = 2 * math.pi * r
        return round(c, 2)


def circle_area(r: int):
    if r <= 0:
        raise Exception("radius cannot be negative")
    else:
        s = math.pi * r * r
        return round(s, 2)