import random


def f(A):
    n = len(A)
    B = [0] * n
    for i in range(n):
        if A[i - 1] == 1 and A[i] == 0:
            B[i] = 1
        elif A[i] == 1 and A[(i + 1) % n] == 1:
            B[i] = 1

    return B


n = int(input())
A = list(map(int, input().split()))
for _ in range(100):
    A = f(A)

c = 0
for i in range(n):
    if A[i] != A[i - 1]:
        c += 1
c //= 2
MOD = 998244353
print(c * pow(n, -1, MOD) % MOD)