fact: Definition topqa r := match r with | Pr55 => Qa5 | (Pr56 | Pr66) => Qa6 | (Pr57 | Pr67 | Pr77) => Qa7 | (Pr58 | Pr68 | Pr78 | Pr88) => Qa8 | _ => Qa9 end.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype path fingraph) fourcolor(hypermap geometry part quiz quiztree)