main :: IO ()
main = do
    [_,a,b] <- (map read . words) <$> getLine
    xs <- (map read . words) <$> getLine
    print $ solve (a, b) xs

solve :: (Int, Int) -> [Int] -> Int
solve (a,b) xs = sum [min (d*a) b | d <- ds]
    where ds = zipWith (-) (tail xs) (init xs)