main = getLine >>= main' . map read . words
    where
        main' [_, a, b] = getLine >>= print . solve a b . map read . words

solve :: Int -> Int -> [Int] -> Int
solve a b = inner 0
    where
        inner acc (x : y : zs) = inner (min ((y - x) * a) b + acc) (y : zs)
        inner acc _ = acc
