import Control.Monad

choco ::Int -> Int -> Int
choco day a =
  length $ 1:[a+1,2*a+1..day]

solve ::Int -> [Int] -> Int -> Int
solve _ [] x = x
solve d (a:as) x =
  solve d as (x + choco d a)

main = do
  n <- read <$> getLine ::IO Int
  [d,x] <- map read . words <$> getLine ::IO [Int]
  al' <- replicateM n $ getLine 
  let al = map read al' :: [Int]
  print $ solve d al x
