Physics help please?

1. A large glider of 243 grams collides with a small stationary glider of 115.6 grams. After the collision, the two gliders are stuck together, and their speed is 1.725 m/s. How much kinetic energy (in Joules) is lost in this perfectly inelastic collision, i.e. what is the difference of the total kinetic energies before and after the collision?