output_description: If the required domino placement doesn't exist, print a single integer `-1`.
  
  Otherwise, output your placement as N strings of N characters each. If a
  square is not covered, the corresponding character must be `.` (a dot).
  Otherwise, it must contain a lowercase English letter. Squares covered by the
  same domino piece must contain the same letter. If two squares have a common
  side but belong to different pieces, they must contain different letters.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
attempt: N = int(input())
  
  if N == 2:
      print(-1)
      exit()
  if N == 3:
      print("aa.")
      print("..a")
      print("..a")
      exit()
  
  
  def f(n, m):
      a = ""
      b = ""
      for i in range(n):
          if i == 2 * m - 2 or i == 2 * m - 1:
              a += "a"
              b += "b"
          elif i == n - 2 * m:
              a += "a"
              b += "a"
          elif i == n - 2 * m + 1:
              a += "b"
              b += "b"
          else:
              a += "."
              b += "."
      print(a)
      print(b)
  
  
  def g(n, m):
      a = ""
      b = ""
      for i in range(n):
          if i == 2 * m - 2:
              a += "a"
              b += "a"
          elif i == 2 * m - 1:
              a += "b"
              b += "b"
          elif i == n - 2 * m or i == n - 2 * m + 1:
              a += "a"
              b += "b"
          else:
              a += "."
              b += "."
      print(a)
      print(b)
  
  
  if N % 4 == 0:
      for i in range(N // 4 - 1):
          f(N, i + 1)
      a = ""
      b = ""
      c = ""
      d = ""
      for i in range(N):
          if i == (N // 2) - 2:
              a += "a"
              b += "d"
              c += "c"
              d += "c"
          elif i == (N // 2) - 1:
              a += "a"
              b += "d"
              c += "b"
              d += "b"
          elif i == N // 2:
              a += "b"
              b += "b"
              c += "a"
              d += "d"
          elif i == (N // 2) + 1:
              a += "c"
              b += "c"
              c += "a"
              d += "d"
          else:
              a += "."
              b += "."
              c += "."
              d += "."
      print(a)
      print(b)
      print(c)
      print(d)
      for i in range(N // 4 - 1):
          g(N, (N // 4) - i - 1)
  
  if N % 4 == 1:
      for i in range(N // 4 - 1):
          f(N, i + 1)
      a = ""
      b = ""
      c = ""
      d = ""
      e = ""
      for i in range(N):
          if i == (N // 2) - 2:
              a += "a"
              b += "a"
              c += "b"
              d += "b"
              e += "a"
          elif i == (N // 2) - 1:
              a += "b"
              b += "c"
              c += "."
              d += "."
              e += "a"
          elif i == N // 2:
              a += "b"
              b += "c"
              c += "."
              d += "."
              e += "b"
          elif i == (N // 2) + 1:
              a += "a"
              b += "."
              c += "a"
              d += "a"
              e += "b"
          elif i == (N // 2) + 2:
              a += "a"
              b += "b"
              c += "b"
              d += "c"
              e += "c"
          else:
              a += "."
              b += "."
              c += "."
              d += "."
              e += "."
      print(a)
      print(b)
      print(c)
      print(d)
      print(e)
      for i in range(N // 4 - 1):
          g(N, (N // 4) - i - 1)
  
  if N % 4 == 2:
      for i in range(N // 4 - 1):
          f(N, i + 1)
      a = ""
      b = ""
      c = ""
      d = ""
      e = ""
      f = ""
      for i in range(N):
          if i == (N // 2) - 3:
              a += "a"
              b += "a"
              c += "b"
              d += "b"
              e += "a"
              f += "a"
          elif i == (N // 2) - 2:
              a += "b"
              b += "b"
              c += "a"
              d += "a"
              e += "b"
              f += "b"
          elif i == (N // 2) - 1:
              a += "a"
              b += "."
              c += "b"
              d += "."
              e += "a"
              f += "."
          elif i == N // 2:
              a += "a"
              b += "."
              c += "b"
              d += "."
              e += "a"
              f += "."
          elif i == (N // 2) + 1:
              a += "."
              b += "b"
              c += "."
              d += "a"
              e += "."
              f += "b"
          elif i == (N // 2) + 2:
              a += "."
              b += "b"
              c += "."
              d += "a"
              e += "."
              f += "b"
          else:
              a += "."
              b += "."
              c += "."
              d += "."
              e += "."
              f += "."
      print(a)
      print(b)
      print(c)
      print(d)
      print(e)
      print(f)
      for i in range(N // 4 - 1):
          g(N, (N // 4) - i - 1)
  
  if N % 4 == 3:
      for i in range(N // 4 - 1):
          f(N, i + 1)
      a = ""
      b = ""
      c = ""
      d = ""
      e = ""
      f = ""
      h = ""
      for i in range(N):
          if i == (N // 2) - 3:
              a += "a"
              b += "b"
              c += "a"
              d += "."
              e += "."
              f += "."
              h += "."
          elif i == (N // 2) - 2:
              a += "a"
              b += "b"
              c += "a"
              d += "."
              e += "."
              f += "."
              h += "."
          elif i == (N // 2) - 1:
              a += "b"
              b += "a"
              c += "b"
              d += "."
              e += "."
              f += "."
              h += "."
          elif i == N // 2:
              a += "b"
              b += "a"
              c += "b"
              d += "."
              e += "."
              f += "."
              h += "."
          elif i == (N // 2) + 1:
              a += "c"
              b += "c"
              c += "."
              d += "b"
              e += "b"
              f += "a"
              h += "a"
          elif i == (N // 2) + 2:
              a += "."
              b += "."
              c += "c"
              d += "a"
              e += "a"
              f += "b"
              h += "b"
          elif i == (N // 2) + 3:
              a += "."
              b += "."
              c += "c"
              d += "b"
              e += "b"
              f += "a"
              h += "a"
          else:
              a += "."
              b += "."
              c += "."
              d += "."
              e += "."
              f += "."
              h += "."
      print(a)
      print(b)
      print(c)
      print(d)
      print(e)
      print(f)
      print(h)
      for i in range(N // 4 - 1):
          g(N, (N // 4) - i - 1)
  
problem_description: Statement
  
  Let us consider a grid of squares with N rows and N columns. You want to put
  some domino pieces on this grid. Each domino piece covers two squares that
  have a common side. Each square can be covered by at most one piece.
  
  For each row of the grid, let's define its quality as the number of domino
  pieces that cover at least one square in this row. We define the quality of
  each column similarly.
  
  Find a way to put at least one domino piece on the grid so that the quality of
  every row is equal to the quality of every column, or determine that such a
  placement doesn't exist.
samples: [{"input": "6", "output": "aabb..\n    b..zz.\n    ba....\n    .a..aa\n    ..a..b\n    ..a..b\n    \n\nThe quality of every row and every column is 2.\n\n* * *"}, {"input": "2", "output": "-1"}]