def _ffmul(a, b):

	r=0

	while a!=0:

		if (a&1)!=0: r^=b

		t=b&0x80

		b=(b<<1)&255

		if t!=0: b^=0x1b

		a>>=1

	return r

g=3

E=[None]*256

L=[None]*256

acc=1

for i in range(256):

	E[i]=acc

	L[acc]=i

	acc=_ffmul(acc, g)

L[1]=0

inv=[E[255-L[i]] if i!=0 else None for i in range(256)]

def ffmul(a, b):

	if a==0 or b==0: return 0

	t=L[a]+L[b]

	if t>255: t-=255

	return E[t]