Exceptions to the recapitulation form include Mozart and Haydn works that often begin with the second subject group when the first subject group has been elaborated at length in the development. If a theme from the second subject group has been elaborated at length in the development in a resolving key such as the tonic major or minor or the subdominant, it may also be omitted from the recapitulation. Examples include the opening movements of Mozart's piano sonata in C minor, KV 457 and Haydn's String Quartet in G major, Op. 77 No. 1.