part2 = do
  text <- readFile "day05-input.txt"
  let input = lines text
      len   = length [x | x <- input, oneLetterBetween x, complexPairs x]
  print len
part2 = do
  text <- readFile "day05-input.txt"
  let input = lines text
      len   = length [x | x <- input, oneLetterBetween x, complexPairs x]
  print len
part2 = do
  text <- readFile "day05-input.txt"
  let input = lines text
      len   = length [x | x <- input, oneLetterBetween x, complexPairs x]
  print len