def solve(n, a):
    o_i = [i for i, x in enumerate(a) if x == 1]

    if len(o_i) <= 1:
        return 1

    w = 1
    for i in range(1, len(o_i)):
        z_b_o = o_i[i] - o_i[i - 1] - 1
        w *= (z_b_o + 1)

    return w

Batch : 2021/22/23/24/25/26