N pawns are placed on a 6x6 chessboard in such a way that taking all the pawns from any three rows and three columns will leave at least one pawn.
What is the minimum possible number of N?
[ You need to be a member of this sitebefore you can submit an answer ]
Today's Bonus: 0 point
Popularity: 84.4 %
Difficulty: 57.1 %