from itertools import pairwise


def main():
    _ = int(input())
    a = list(map(int, input().split()))
    
    mod = 10 ** 9 + 7
    while len(a) > 1:
        a = [(x + y) % mod for x, y in pairwise(a)]

    ans = a[0]
    print(ans)


if __name__ == "__main__":
    main()