short scanmap[32*8] = {
	 0,  4,  8, 12, 16, 20, 24, 28,
	32, 36, 40, 44, 48, 52, 56, 60,
	64, 68, 72, 76, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1,
	 1,  5,  9, 13, 17, 21, 25, 29,
	33, 37, 41, 45, 49, 53, 67, 61,
	65, 69, 73, 77, -1, -1, -1, -1,
	-1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -