N, A, B = map(int, input().split())
K = []
for _ in range(N + 1):
    k = int(input())
    K.append(k)

ans = 0
bb = 27720
for i in range(N + 1):
    ans += (B ** (i + 1)) * bb * K[i] // (i + 1)
    ans -= (A ** (i + 1)) * bb * K[i] // (i + 1)
# print(ans)
print(ans // bb)