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

def func(x):
    ans = 0
    a = x
    for i, k in enumerate(K):
        ans += k*a*(LCM//(i+1))
        a *= x
    return ans

LCM = 27720
print((func(B)-func(A))//LCM)