ধর $$f\left( x \right) = \max \left\{ {\left| {x + 1} \right|,\left| {x + 2} \right|,......,\left| {x + 5} \right|} \right\}$$। তাহলে $$\mathop \smallint \limits_{ - 6}^0 f(x)dx$$ সমান___________।