How to find the subnet mask for 800 computers if the subnet is class B?

Question

Network administration

I read on Wikipedia that the class C subnet mask for 30 computers is calculated by the formula 2 ^ 8 - (n + 2) , where n is the number of computers in the subnet.
There was a need to define a class B subnet mask for 800 computers. As far as I understand, for class B, the deuce must be raised to the 16th power.
I got: 2^16 - (800 + 2) = 64734 . What now needs to be done with the number 64734 to find out the subnet mask? Thank you!