import collections

yuki_Hotel = int(input())
next_Hotel = int(input())
n = int(input())
Hotels = []
price = 0

for count in range(n):
    list = input()
    Hotels.append(list)

c = collections.Counter(Hotels)
for hotel in c:
    if c[hotel] >= 2:
        a = c[hotel] - 1
        price += (a* yuki_Hotel) + (a * next_Hotel)
print(price)