Yukiprice = int(input())
otherprice = int(input())
N = int(input())
room_numbers = []
deadcount = 0


for i in range(N):
    room_numbers.append(int(input())) 
    
#リスト内を昇順ソート
sorted(room_numbers)
#print(room_numbers[2])

#n = n+1　なら損出計算
n = 0
for i in range(N-1):
    if room_numbers[n] == room_numbers[n+1]:
        deadcount += 1
    n += 1
        
#損出の合算

lose_sum = deadcount*(Yukiprice + otherprice)

#print(deadcount)
print(lose_sum)