The squares of an 8 x 8chessboard are mistakenly colored in the blocks of two colors as shown in the figure below. You need to cut this board along some lines separating its rows and columns so that the standard 8 x 8 chessboard can be reassembled form the pieces obtained. What is the minimum number of pieces into which the board needs to be cut?

The answer is an integer. Just put the number without any decimal places.