output_description: Print a $8 \times 8$ chess board by strings where a square with a queen is
  represented by 'Q' and an empty square is represented by '.'.
input_description: 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.
attempt: from itertools import permutations
  import sys
  
  read = sys.stdin.read
  readline = sys.stdin.readline
  readlines = sys.stdin.readlines
  
  
  def main():
      k, *rc = map(int, read().split())
  
      tmp = []
      ng_list_add = []
      ng_list_sub = []
      for pattern in permutations(range(8)):
          flag = True
          for r, c in enumerate(pattern):
              if r + c in ng_list_add or r - c in ng_list_sub:
                  flag = False
                  break
              ng_list_add.append(r + c)
              ng_list_sub.append(r - c)
          if flag:
              tmp.append(pattern)
          ng_list_add = []
          ng_list_sub = []
  
      RC = []
      for r, c in zip(*[iter(rc)] * 2):
          RC.append((r, c))
  
      ans_place = None
      for p in tmp:
          flag = True
          for r, c in RC:
              if p[r] != c:
                  flag = False
                  break
          if flag:
              ans_place = p
              break
  
      ans = []
      for i in ans_place:
          line = "." * i + "Q" + "." * (7 - i)
          ans.append(line)
  
      print("\n".join(ans))
  
  
  if __name__ == "__main__":
      main()
  
problem_description: 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.
  
  ![](https://judgeapi.u-aizu.ac.jp/resources/images/IMAGE2_ALDS1_13_A_8queens)  
  
  For a given chess board where $k$ queens are already placed, find the solution
  of the 8 queens problem.
samples: [{"input": "2\n    2 2\n    5 3", "output": "......Q.\n    Q.......\n    ..Q.....\n    .......Q\n    .....Q..\n    ...Q....\n    .Q......\n    ....Q..."}]