A stone is dropped from a cliff. At the same instant, a projectile is launched vertically upward from the ground below the cliff. The height of the projectile, $h_P(t)$, in meters, is given by $h_P(t)=-4.9t^2+29.4t$. The height of the stone, $h_S(t)$, in meters, is given by $h_S(t)=C-4.9t^2$, where $C$ is the initial height of the cliff. If both objects reach the same maximum height, what is the initial height of the cliff, $C$?