def yukicoder1081(N, A):
    for i in range(N - 1, 0, -1):
        for j in range(i):
            A[j] = A[j] + A[j + 1]
    return A[0] % (10 ** 9 + 7)

N, *A = map(int, open(0).read().split())
print(yukicoder1081(N, A))