Step 1: Evaluating inverse trigonometric values.
\[
\cos^{-1} \frac{1}{2} = \frac{\pi}{3}, \quad \sin^{-1} (1) = \frac{\pi}{2}, \quad \tan^{-1} \frac{1}{\sqrt{3}} = \frac{\pi}{6}
\]
Step 2: Summing up the values.
\[
\frac{\pi}{3} + \frac{\pi}{2} + \frac{\pi}{6} = \pi
\]