Fly to the sky

Ski jumping is a sport in which skiers go down a take-off ramp, jump and attempt to land as far as possible down the hill below. If the length and height of the ramp are $90$ m and $50$ m, respectively, and the weight of skier is $100$ kg, then how much potential energy can the skier use? (The magnitude of the gravitational acceleration is 9.8 m/ $s^2$ .)