Can you solve without modifying the integrand? (My twelfth integration problem)

Calculus Level 3

\[ \large \int_{0}^{1} \sqrt{1+\dfrac{x^{2}}{1-x^{2}}} \, dx \]

If this integral can be expressed in the really nice form of \( \dfrac{a \pi}{b} \), where \(a, b\) are coprime positive integers, find \(a+b\).