import sys
import math


def main():
    it = iter(map(int, sys.stdin.read().split()))

    v = [next(it) for _ in range(3)]
    n = v[0]
    a = v[1]
    b = v[2]
    k = [next(it) for _ in range(n + 1)]

    d = 1
    for i in range(1, n + 2):
        d = d * i // math.gcd(d, i)
    s = 0

    for i in range(n + 1):
        pb = pow(b, i + 1)
        pa = pow(a, i + 1)
        diff = pb - pa

        coef = k[i]
        mul = d // (i + 1)

        term = coef * diff * mul
        s += term
    ans = s // d

    print(ans)


if __name__ == "__main__":
    main()