fac  0 = 1
fac n = n * fac (n - 1)

summ [] = 0
summ (l:z) = l + summ z

foldll _ a [] = a
foldll f a (l:b) = let
        na = f a l
        in foldll f na b

summ2 = foldll (+) 0  

-- qs::[Int] -> [Int]
qs [] = []
qs (pivot:zb) = let
        mensi = filter (< pivot) zb
        vetsi = filter (>= pivot) zb
        in qs mensi ++ [pivot] ++ qs vetsi

ms:: [Int] -> [Int]

ms [] = []
ms s = let
        ss = map (\ a->[a]) s
        reduce [a]= [a]
        reduce [] = []
        reduce (h1:(h2:t)) = merge h1 h2 : reduce t
        mreduce [a] = a
        mreduce s = mreduce $ reduce s
        merge [] s = s
        merge s [] = s
        merge (h1:t1) (h2:t2) = if h1 < h2 then h1:merge t1 (h2:t2) 
                                else h2:merge (h1:t1) t2
        in
        mreduce ss

f a = f [a]

main = do
        putStrLn (show ( ms [5,1,4,2,3] ))