from math import factorial
fac11=factorial(11)
N,A,B=map(int,input().split())
ap=1
bp=1
ans=0
for i in range(N+1):
  K=int(input())
  ap*=A
  bp*=B
  ans+=(bp-ap)*K*fac11//(i+1)

print(ans//fac11)