import strutils, sequtils, tables
proc getInt: int = stdin.readLine.parseInt

# Yuki/振替先ホテルの料金, 予約の件数
let P1, P2, N = getInt()

var
  R = initCountTable[int]()   #予約された部屋番号
  cost = 0

for n in 0 ..< N: R.inc getInt()

while R.largest.val > 1:
  let maxR = R.largest
  cost += (P1 + P2) * (maxR.val - 1)
  R[maxR.key] = 0

echo cost