MOD = 10 ** 9 + 7
n = int(input())
a = list(map(int, input().split()))
for i in range(n - 1):
    b = [0] * (len(a) - 1)
    for j in range(len(b)):
        b[j] = a[j] + a[j + 1]
    a = b[:]
print(a[0] % MOD)