Provide your best answer for the following math problem. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The problem is: if one positive integer is greater than another positive integer by 3 , and the difference of their cubes is 63 , what is their sum ?
5
27 + 11 = 38.