The first step is to figure out what the brick’s hodograph looks like; it is useful to consult European Physics Olympiad Problem No 2 from 2023. The second step is to integrate u_y over time: l_y=\int u_y\mathrm dt=\int u_y\frac{\mathrm du_x}{a_x}, where the x-component of the acceleration, a_x, can be expressed in terms of a_0 and the relevant angles.
Please submit the solution to this problem via e-mail to physcs.cup@gmail.com.