import sys
input = sys.stdin.readline

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

MM=11*9*8*7*5
ANS=0

for i in range(N+1):
    x=K[i]
    ANS+=x*(B**(i+1)-A**(i+1))*MM//(i+1)

print(ANS//MM)