stableTail :: Eq a => [a] -> a
stableTail (x : y : ys) =
  if x == y
  then x
  else stableTail (y : ys)
stableTail :: Eq a => [a] -> a
stableTail (x : y : ys) =
  if x == y
  then x
  else stableTail (y : ys)
stableTail (x : y : ys) =
  if x == y
  then x
  else stableTail (y : ys)