 Performance of classical music repertoire requires a proficiency in sight-reading and ensemble playing, harmonic principles, strong ear training (to correct and adjust pitches by ear), knowledge of performance practice (e.g., Baroque ornamentation), and a familiarity with the style/musical idiom expected for a given composer or musical work (e.g., a Brahms symphony or a Mozart concerto).The key characteristic of European classical music that distinguishes it from popular music and folk music is that the repertoire tends to be written down in musical notation, creating a musical part or score.This score typically determines details of rhythm, pitch, and, where two or more musicians (whether singers or instrumentalists) are involved, how the various parts are coordinated.