def arc_length(d,a):
    
    pi=22/7
    if a >= 360:
        return None
    arclength = (pi*d) * (a/360)
    return arclength
def is_not_prime(n):
    import math
    
    result = False
    for i in range(2,int(math.sqrt(n)) + 1):
        if n % i == 0:
            result = True
    return result