If you know all of the notes, you can input it as:
PLAY "O4ABCDEFGO2ABC" (ABCDEFG being notes, O1-4 being octaves, and using + or - for sharp and flat)
Unfortunatly this only works if you know every note, and I'm not sure if it can do multiple notes at the same time (I use QBasic, so I don't know what the newer ones can do).