Find the speed of the plane?

A high-performance jet plane, practicing radar avoidance maneuvers, is in horizontal flight 35.0 m above the level ground. Suddenly, the plane encounters terrain that slopes gently upward at 4.10�, an amount difficult to detect. How much time does the pilot have to make a correction to avoid flying into the ground ( s)? The speed of the plane is 1250 km/h.