Danielle divides a $30 \times30$ board into $100$ regions that are $3 \times 3$ squares squares each and then paint some squares black and the rest white. Then to each region assigns it the color that has the most squares painted with that color. a) If there are more black regions than white, what is the minimum number $N$ of cells that Danielle can paint black? b) In how many ways can Danielle paint the board if there are more black regions than white and she uses the minimum number $N$ of black squares?