Piano Sonata No. 31 in A-Flat Major, Opus 110 - Piano Sonata No. 31 in A-Flat Major, Op. 110: I. Moderato cantabile, molto espressivo (降A大调第31号钢琴奏鸣曲，作品110 - 如歌的行板 - 非常富有表现力的)