Let $y = y_{1}(x)$ and $y = y_{2}(x)$ be two distinct solutions of the differential equation $\dfrac{dy}{dx} = x + y$, with $y_{1}(0) = 0$ and $y_{2}(0) = 1$ respectively. Then, the number of points of intersection of $y = y_{1}(x)$ and $y = y_{2}(x)$ is