# はじにある1は足したほうがよい
N = int(input())
A = list(map(int,input().split()))

from collections import deque
q = deque(A)
DIV = 10 ** 9 + 7

ans = 0
while q:
    found = False
    if q[0] == 1:
        ans += 1
        q.popleft()
        found = True
    elif q[-1] == 1:
        ans += 1
        q.pop()
        found = True
    if not found:
        break
    
def f(X):
    res = 1
    for x in X:
        res *= x
        res %= DIV
    return res
    
print((ans + f(q)) % DIV)