this is a very difficult question.
If you just divide it, it won't be the correct answer. since this filing is a ball.
There are gaps between balls, if you just divided the volumn of the cube, by the volumn of the ball. Your answer will include some balls that are *melted* and fills in all the gap between balls.
So, you should think about that problem.
To solve yours, to convert all INTs to FLOAT and do the calculation.