Indian classical music is the art music of the Indian subcontinent. Bharat's Natyashastra was the first treatise laying down fundamental principles of dance, music, and drama. Indian classical music is both elaborate and expressive. Like Western classical music, it divides the octave into 12 semitones of which the 7 basic notes are, in ascending tonal order, Sa Re Ga Ma Pa Dha Ni for Hindustani music and Sa Ri Ga Ma Pa Dha Ni for Carnatic music, similar to Western music's Do Re Mi Fa So La Ti . However, Indian music uses just-intonation tuning, unlike most modern Western classical music, which uses the equal-temperament tuning system. Also, unlike modern Western classical music, Indian classical music places great emphasis on improvisation.