import math
import sys
from fractions import Fraction
from typing import List, Tuple


def int1(x: str, /): return int(x) - 1


def input(): return sys.stdin.readline().rstrip('\n')


def dbg(*args, **kwargs):
    print(*(repr(arg) for arg in args), *(f'{k}: {repr(v)}' for k, v in kwargs.items()),
          sep='; ', file=sys.stderr, flush=True)


def main():
    n, a, b = map(int, input().split())
    ans = 0
    for i in range(n + 1):
        ans += Fraction(int(input()) * (b ** (i + 1) - a ** (i + 1)), i + 1)
    return math.floor(ans)


def _start():
    ret = main()

    if ret is not None:
        if isinstance(ret, List) or isinstance(ret, Tuple):
            print(*ret)
        else:
            print(ret)


if __name__ == '__main__':
    _start()