1a
 1a
  1c
  2d
 2b
  1c
  2d
 3a
  1c
  2d
 4b
  1c
  2d
2b
 1a
  1c
  2d
 2b
  1c
  2d
 3a
  1c
  2d
 4b
  1c
  2d