任拓

-- -- 定义 sum 函数
-- import Prelude hiding (sum)
-- sum :: Int -> Int -> Int
-- sum n 1 = n
-- sum n m = n + sum (n + 1) (m - 1)

-- main :: IO ()
-- main = print (sum 1 9) -- 主函数，打印结果


fibonacci :: Int -> Int
fibonacci 0 = 1
fibonacci 1 = 1
fibonacci n = fibonacci (n - 2) + fibonacci (n - 1)

main :: IO ()
-- main = print (fibonacci n) where n = 10
main = print (fibonacci 10)