a-a aaa aad aan aap aax ad- ada add adn adp adx an- ana and ann anp anx ap- apa apd apn app apx ax- axa axn axp axx daa dad dan dap dax dda ddd ddn ddp ddx dna dnd dnn dnp dpa dpd dpn dpp dxd dxn dxp dxx naa nad nan nap nax nda ndd ndn ndp nna nnn nnp npa npd npn npp nxd p-p paa pad pan pap pax pda pdd pdn pdp pdx pn- pna pnd pnn pnp pnx ppa ppd ppn ppp ppx xaa xad xan xap xda xna xpa xpd xpn xpp xxp xxx