package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)

func nextInt() int {
	sc.Scan()
	i, err := strconv.Atoi(sc.Text())
	if err != nil {
		panic(err)
	}
	return i
}

func main() {
	sc.Split(bufio.ScanWords)
	p1 := nextInt()
	p2 := nextInt()
	n := nextInt()
	rs := make(map[int]struct{})
	for i := 0; i < n; i++ {
		rs[nextInt()] = struct{}{}
	}
	fmt.Println((n - len(rs)) * (p1 + p2))
}