6. Consider the following variation of the n-Queens Problem:

If some of the squares that would be attacked by the placement are obstructed by the placement of pawns on an n x n chessboard, can more than n-Queens be placed on the partial board that remains? For example, if five pawns are added to a 3 × 3 chessboard, then four non-attacking Queens may be placed on the board (Figure 3.30).