[POI2012]RAN-Rendezvous题目描述ByteasarisarangerwhoworksintheArrowCave-afamousrendezvousdestinationamonglovers.Thecaveconsistsof\(n\)chambersconnectedwithone-waycorridors.Ineachchamberexactlyoneoutgoingcorridorismarked