n,a,b = map(int, input().split())
k = [int(input()) for _ in range(n+1)]

ans = 0
r = b
l = a
res = 0
for i in range(n+1):
    ans += (r - l) * k[i] // (i+1)
    res += ((r - l) * k[i] % (i+1)) / (i+1)
    r *= b
    l *= a    

print(ans + int(res))