bbbb bbbs bibb bibi bibs biis birb biri birr birs biry bis- biss bisy biys bris brrr brrs brsb brsr bry- bysb bysi byss bysy i-by ibis ibri ibss ibyi iiii iiis iirs iisi iisr irby iri- iris iriy irri irrs isis isri issi issr isss issy isys rbbb rbbr rbbs rbis rbss rib- ribs riby riis riri rirs risi riss rrrr rsbi rsis ryis rysy s-ib s-ii sbbs sbsi sibi sibs siby siri sirr sirs sisi siss sisy siyi srby srib sris ssbr ssby ssis ssri ssrs sssb sssi ssss syis syrs syry syss ybbs ybry yirb yirr yiss ysby ysii ysyb yyyy