The present invention is directed to tricyclic compounds of the formula wherein all substituents are defined herein, as well as pharmaceutically acceptable compositions comprising compounds of the invention and methods of using said compositions in the treatment of various disorders.本發明係關於下式之三環化合物其中所有取代基在本文中定義,以及包含本發明化合物之醫藥學上可接受之組合物及在治療各種病症中使用該等組合物之方法。