${\cos ^{ - 1}}(\cos ( - 5)) + {\sin ^{ - 1}}(\sin (6)) - {\tan ^{ - 1}}(\tan (12))$ is equal to :(The inverse trigonometric functions take the principal values)

Question

${\cos ^{ - 1}}(\cos ( - 5)) + {\sin ^{ - 1}}(\sin (6)) - {\tan ^{ - 1}}(\tan (12))$ is equal to :

(The inverse trigonometric functions take the principal values)

3$\pi$ $-$ 11