A chessboard is an 8 x 8 grid of cells. Within each column and within each row, cells alternate between black and white. The cell in the upper left corner (0, 0) is white. You are given a String board, where the j-th character of the i-th element is 'F' if the cell in the j-th column from the left and i-th row from the top is occupied, or '.' if it is empty. Return the number of occupied white cells on the board.
|-||board will contain exactly 8 elements.|
|-||Each element of board will contain exactly 8 characters.|
|-||board will contain only the characters '.' and 'F'.|