Three identical smooth spheres, A, B and C, of masses 2m, M and m, respectively, are resting on a smooth, horizontal surface. The coefficient of restitution between A and B is 4/5, and the coefficient of restitution between B and C is 1/2. Sphere A is projected towards B with velocity 2u. Given that A, B and C are collinear, and that the velocity of B is zero after it collides with C, find the loss in kinetic energy after the second collision.