import Control.Monad (replicateM)
import Data.List (sort)

rInt :: String -> Int
rInt = read

solve _ n [] = [n]
solve k n (r:rs)
    | k == r    = solve k (n + 1) rs
    | otherwise = n : solve r 0 rs

main = do
    p1 <- readLn
    p2 <- readLn
    n <- readLn
    rs <- sort . map rInt <$> replicateM n getLine
    print $ foldr (\x y -> (p1 + p2) * x + y) 0 $ solve (head rs) 0 (tail rs)