P1 = int(input())
P2 = int(input())
N = int(input())
r = list()
x = set()

for i in range(N):
    Ri = int(input())
    r.append(Ri)
    x.add(Ri)

R = len(r)
X = len(x)
lost = (P1+P2)*(R-X)

print(lost)