8 Queens Problem
The goal of 8 Queens Problem is to put eight queens on a chess-board such that none of them threatens any of others. A queen threatens the squares in the same row, in the same column, or on the same diagonals as shown in the following figure.
For a given chess board where k queens are already placed, find the solution of the 8 queens problem.
In the first line, an integer k is given. In the following k lines, each square where a queen is already placed is given by two integers r and c. r and c respectively denotes the row number and the column number. The row/column numbers start with 0.
Print a 8×8 chess board by strings where a square with a queen is represented by 'Q' and an empty square is represented by '.'.