How many bytes have their second, third, and fourth digit equal to 0.
If we refer to 8-bits, we would have a value from 00000000 to 11111111, there would be a total of 256 values.

Considering that we only need it to have its second, third and fourth digit equal to 0, we can add the values from 2^0 up until 2^4

That would be equal to 31 bytes.