k-on!!, k-on series, running, multiple girls, kotobuki tsumugi, nakano azusa, sakuragaoka high school uniform, glasses, school uniform, hirasawa yui, blonde hair, 4girls, brown hair, long hair, guitar, instrument, black hair, instrument case, brown eyes, tainaka ritsu, akiyama mio, guitar case, twintails, parody, 5girls