function LCS(a, b)
	if length(a) = 0 or length(b) = 0 then return ""
	while length(b)
		for j = length(b) to 1 step -1
			if instr(a, left(b, j)) then return left(b, j)
		next j
		b = mid$(b, 2)
	end while
end function

print LCS("thisisatest", "testing123testing")
end