A hot-air balloon of diameter \(10 \mathrm{~m}\) rises vertically at a constant speed of \(12 \mathrm{~m} / \mathrm{s}\). A passenger accidentally drops his camera from the railing of the basket when it is \(18 \mathrm{~m}\) above the ground. If the balloon continues to rise at the same speed, how high is the railing when the camera hits the ground?