bbbb bbci bbrc bcbc bccc bcci bcit bctc bibb bibi bicc bici birb biri birr birt bitc bitt brcb bric brit brrr brtc btcc btrc btrt bttb cbbc cbcc cbcr cbct cbir cbit cbrt cbtc ccbc cccb cccc ccci ccic ccii ccir ccrc ccri ccrt cctb cctc cctt cibc cibi cicc cici cicr cict ciii ciit cirb circ ciri cirr cirt citb citi citt crbc crcc crcr crib cric crit crrt crtc ctbi ctic ctrc ibrc ibri ibtb ibtc icbc iccb iccc icci iccr icct icrc icrr icrt iiii iiit iirc iitr iitt ircc iri- iric irrc irri irti itic itri rbbb rbbr rcbc rccb rccc rcic rctc rcti rib- ricc rict riri riti ritt rrrr rtcc tbcb tbcc tbit tbrb tccc tctc tibi ticc tiit tirb tiri tirr titc titi titt trcc tri- trib tric trit trtc trtr ttbb tttt