a a x1 b b b x1 a x1 d c d x1 b b b x1 a f x1 b b x1 c c c x1 c c x1 d d d x1 c d d x1 f x1 f f x1 f a x1 a 1 b 1 d 1 c 1 f 1 FULL ./SRS/Zantema/z123.srs