Let \( f:\mathbb{R}\to\mathbb{R} \) and \( g:\mathbb{R}\to\mathbb{R} \) be defined as where \( a, b \) are non-negative real numbers. If \( (g\circ f)(x) \) is continuous for all \( x\in\mathbb{R} \), then \( a+b \) is equal to ____________.