#!/usr/bin/env python
# -*- coding: utf-8 -*-

def main():
    P1 = int(input())
    P2 = int(input())
    N = int(input())
    l = []
    for i in range(N):
        l.append(int(input()))
    print((P1 + P2) * (N - len(set(l))))

if __name__ == '__main__':
    main()