import Data.List

f::[(Int,Int)]->[(Int,Int)]->Int->Int->Int
f [] _ _ ans=ans
f _ [] _ ans=ans
f xs2@((x,c1):xs) ys2@((y,c2):ys) n ans
      |x+y<n=f xs ys2 n ans
      |x+y>n=f xs2 ys n ans
      |otherwise=f xs ys n (ans+c1*c2)

main = do
       e<-getLine
       e2<-getLine
       let ts=map read (words e2)::[Int]
           xs=group $ sort $ ts
           ys=reverse xs
           (n:x:[])=map read (words e)::[Int]
           zs1=zip (map head xs) (map length xs)
           zs2=zip (map head ys) (map length ys)
       print $ f zs1 zs2 x 0