main :: IO ()
main = do
  [n, a, b] <- getInts
  xs <- getInts
  print $ solve xs a b

getInts :: IO [Int]
getInts = map (read :: String -> Int) . words <$> getLine

solve :: [Int] -> Int -> Int -> Int
solve xs a b = go xs (0, 0) 
  where
    go :: [Int] -> (Int, Int) -> Int 
    go (y:ys) (n, m)
     | null ys = n*a + b*m
     | otherwise = if (head ys - y) * a > b
                   then go ys (n, m+1)
                   else go ys (n+(head ys - y), m)