x 0 0 [1,3,5] =
--      mediaaux (0+1) (0+1) [3,5]
--      mediaaux 1 1 [3,5]
--      mediaaux (1+3) (1+1) [5]
--      mediaaux 4 2 [5]
--      mediaaux (4+5) (2+1) []
--      mediaaux 9 3 []
--      9/3
--      3


mediao l = mediaaux 0 0 l


-- medi
mediao l = mediaaux 0 0 l
mediao l = mediaaux 0 0 l