def fastmod(z, t):
    if t != 3 and t != 9:
        print("Cannot be done")
        return
    if isinstance(z, int):
        nz = z
        while nz > 10:
            a = 0
            nz = str(nz)
            for i in nz:
                a=a+int(i)
            nz = a
        return nz % t

print(fastmod(99999, 3))