collatz :: Int -> Int
collatz n
    | n `mod` 2 == 0 = n `div` 2
    | otherwise      = 3 * n + 1
collatz :: Int -> Int
collatz n
    | n `mod` 2 == 0 = n `div` 2
    | otherwise      = 3 * n + 1
collatz n
    | n `mod` 2 == 0 = n `div` 2
    | otherwise      = 3 * n + 1