-er a-a a-t aaa aae aap aar aat aax aea aee aep aer aet aex ap- apa ape app apr apt apx ar- ara are arp arr art arx at- ata ate atp atr att atx ax- axa axe axp axr axt axx eaa eae eap ear eat eax eea eee eep eer eet eex ep- epa epe epp epr ept epx era ere erp err ert eta ete etp etr ett etx ex- exa exe exp exr ext exx p-p paa pae pap par pat pax pea pee pep per pet pex ppa ppe ppp ppr ppt ppx pra pre prp prr prt prx pt- pta pte ptp ptr ptt ptx pxe pxr pxt ra- raa rae rap rar rat rax re- rea ree rep rer ret rex rpa rpe rpp rpr rpt rpx rra rrp rrr rrt rta rte rtp rtr rtt rtx rxp rxr t-x taa tae tap tar tat tax te- tea tee tep ter tet tex tpa tpe tpp tpr tpt tpx tra tre trp trr trt trx tta tte ttp ttr ttt ttx txe txt xaa xap xar xat xee xep xer xet xex xpa xpe xpp xpt xrt xrx xtp xtr xtx xxp xxx