"The first type of music" - suitable for listening to when walking include: Chopin's "Glorious Grande Waltz", almost all the songs in "Chopin Waltz Collection", Liszt's "The Bell", Mozart's "Turkish March", Beethoven's "Tahara". "Second type of music" - suitable for listening to while sleeping include Beethoven's "For Alice" and "Moonlight Sonata", Chopin's "Farewell Etude" and "Raindrop Prelude", Liszt's three "Love" "The Dream", Debussy's "Reflection in the Water", "Moonlight", Bandari's "First Snow", "The Mark of the Rain", etc., Hisaishi Joe's "Castle in the Sky", "The Summer of Kikujiro", etc. "Third type of music" - If you want to listen to music while studying, you can listen to the music you listen to while sleeping (the second type of music). "Category 4 music" - music that aids memory, similar to Category 2 and Category 3.