# import sys; input = sys.stdin.buffer.readline
# sys.setrecursionlimit(10**7)
from collections import defaultdict
con = 10 ** 9 + 7; INF = float("inf")

def getlist():
	return list(map(int, input().split()))

#処理内容
def main():
	P1 = int(input())
	P2 = int(input())
	D = defaultdict(int)
	N = int(input())
	for i in range(N):
		R = int(input())
		D[R] += 1

	ans = (P1 + P2) * (N - len(D))
	print(ans)

if __name__ == '__main__':
	main()