need help with finding mass and height of the ball?

Question

https://i.stack.imgur.com/KIRkO.png

I have : h =1.7m , M = 0.65 kg, v i = sqrt 2gh = 5.77

vf = 2m / M + m (-vi) + m-M / m+M (vi) = 0.

But this cannot be reduced because there are too many m's. How then can it be solved?