Can someone please help me out on the below problem?

PROBLEM: How do we find out the force exerted by A on B ?
                Will the calculation vary if Body B does not
                deform?
SITUATION:
Body A hits body B causing a deformation of body B. Assume
B is a cuboid.
Known values:
1) Mass of body A
2) Mass of body B
3) Velocity before impact of body A
4) Velocity before impactof body B
5) Dimensions of the B before and after impact (for simplicity
    sake, let's assume that B has reduced in length by x
    meters and there is no other change in the dimension)
6) Assume that both body A & B come to rest after impact.

Thanks in Advance.