foo n
  | n < 0             = 0
  | n `mod` 17 == 2   = -43
  | otherwise         = n + 3
foo n
  | n < 0             = 0
  | n `mod` 17 == 2   = -43
  | otherwise         = n + 3
foo n
  | n < 0             = 0
  | n `mod` 17 == 2   = -43
  | otherwise         = n + 3