p1 = int(input())
p2 = int(input())
n = int(input())
count = 0

rooms = [input() for i in range(n)]

for i in range(len(rooms)):
    room = rooms.pop()
    if room in rooms:
        count += 1
        

if count:
    damage = (p1 + p2) * count
    print(damage)
else:
    print(0)