Instructions: Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.
Input: Dreimal sieben Gedichte aus Albert Girauds ''Pierrot lunaire'' (''Three times Seven Poems from Albert Giraud's 'Pierrot lunaire'''), commonly known simply as Pierrot Lunaire, Op. 21 (''Moonstruck Pierrot'' or ''Pierrot in the Moonlight''), is a melodrama by Arnold Schoenberg.
Output:
Which is the basis of Pierrot Lunaire?