Improve? the Great

Create a token that is a copy of target creature
on the battlefield. Roll a 20 sided die. If 19 or
less, put +1/+1 counters on the token equal to
the number rolled times X, which is the
difference between the total power of the
creatures you control prior to Improve? the
Great being cast and the amount of deserts
on the battlefield. If 20, the token enters the
battlefield -1/-1 counters equal to the amount
of characters in this sentence.