a-a aaa aaf aap aar aas af- afa aff afp afr afs ap- apa apf app apr aps ar- ara arf arp arr ars as- asa asf asp asr ass faa faf fap far fas ffa fff ffp ffr ffs fpa fpp fpr fps fra frf frp frr frs fsa fsf fsp fsr fss p-p paa paf pap par pas pfa pff pfp pfr pfs ppa ppf ppp ppr pps pra prf prp prr prs ps- psa psf psp psr pss ra- raa raf rap rar ras rfa rff rfp rfr rfs rpa rpf rpp rpr rps rra rrf rrp rrr rrs rsa rsf rsp rsr rss saa saf sap sar sas sfa sff sfp sfr sfs spa spf spp spr sps sr- sra srf srp srr srs ss- ssa ssf ssp ssr sss