a-a aaa aad aap aar aax ad- ada add adp adr adx ap- apa apd app apr apx ar- ara ard arp arr arx ax- axa axp axr axx daa dad dap dar dax dda ddd ddp ddr ddx dpa dpd dpp dpr dra drd drp drr drx dxd dxp dxr dxx p-p paa pad pap par pax pda pdd pdp pdr pdx ppa ppd ppp ppr ppx pra prd prp prr prx pxr ra- raa rad rap rar rax rda rdd rdp rdr rdx rpa rpd rpp rpr rpx rra rrd rrp rrr rxp rxr xaa xad xap xar xda xdr xpa xpd xpp xrd xrx xxp xxx