-- The function m is known as the McCarthy 91 function. The function n
-- is a simpler function doing the same. Well, does it? Perhaps we
-- should proof that both functions do the same...
m :: Int -> Int
m x
| x > 100 = x - 10
| otherwise = m $ m $ x + 11
n :: Int -> Int
n x
| x > 100 = x - 10
| otherwise = 91
main = do
print $ map m [80..120]
print $ map n [80..120]