主谱F段基于肖邦第一叙事曲coda部分改编而来，由于难度较大，
故在主谱中相应段落关联了相对简单的ossia版本，即F段有两个版本，
视频共两部分，分别对应不同的版本，
同一个视频中同一段落的不同版本用灰白midi音符显示。
Section F of the main melody is adapted from the coda part of Chopin's Ballade I:g minor.
Due to its high difficulty level,therefore,in the main sepctrum,the corresponding sections are associated with relatively simple ossia version.Specifically,there are 2 versions for F section.
The vedio consists of 2 parts,corresponding to different versions respectively.
Different versions of the same paragragh in the same vedio are dieplayed using gray midi notes.
