package main

import "fmt"

func main() {
	var py, pa, n int
	fmt.Scan(&py, &pa, &n)
	r := make(map[int]int, 0)
	for i := 0; i < n; i++ {
		var room int
		fmt.Scan(&room)
		r[room]++
	}
	ans := 0
	for _, v := range r {
		ans += (v-1)*py + (v-1)*pa
	}
	fmt.Println(ans)
}