Landlord, this problem is actually a math problem, a nine-story hollow square, it is not difficult to see that the outer layer has four more children than the adjacent inner layer, so this problem can be regarded as, knowing a arithmetic progression, the tolerance is 4, there are 9 numbers, and their sum is 432, so find the first item a0.

So a0=32, that is, the innermost layer uses 32 words, with 8 words on each side.