rcbo rccb rccc rcep rcgc rcnr rcon rcpo rcrg rebb rebe rebo rebu recc rece recp recr recu reeb reen reep rege regn rego regr regu rene reng renn reno renu reog reop reou repe repo repp repr repu rere rerg rero reru reue reup reuu rgbe rnbr rnco rncp rob- robb robe robo robu rocc roce roco roeg roen roer roge rogg rogo ronc rone rong rono roob roog roon roop roor rope ropo rorc rore roro roru roub roue roun roup rpob rpoe rpon rppn rrrr rrun rubb rube rubp rubu ruce ruen ruer ruge rugg runc rune rung runn runo rupe rupp rurc rure ruro rurp ruru ruun u-rp ubbe ubbo uber uboc ubon ubpc ucbc uccp ucon ucpb ucrc ueno ugcc ugcg ugeo ugep uggo ugne ugro ugur uguu unbe uncc unce uncg unco uncp uneb unec unee unen uner ungo ungp ungu unne unno unon unop unpc unro uocc uone uor- uore upbe upen upgo upne upnp upon upor uppc uppe uppp uppu upup urbe ure- urge urgu urne uro- uroo urpo urre urun urup urur uucp uuen uuno uuoc uuuu