Concerto For Pianoforte And Orchestra No. 5 In E-Flat Major, Op. 73 - Concerto For Pianoforte And Orchestra, No.5, E Flat Major, Opus 73, I: Allegro (降E大调第5号钢琴与管弦乐团协奏曲，作品73 - 第一乐章 快板)