print multInv(42, 2017)
end

sub multInv(a,b)
	x0 = 0
	b0	= b
	multInv	= 1
	if b = 1  return
	while a > 1
		q	= a / b
		t	= b
		b	= mod (a, b)
		a	= t
		t	= x0
		x0	= multInv - q * x0
		multInv	= int(t)
	wend
	if multInv < 0  return multInv + b0
end sub