n = int(input())
a = input()

while n > 0 and a[0] == '1':
    a = a[1:]
    n -= 1

while n > 0 and a[-1] == '0':
    a = a[:-1]
    n -= 1

if n == 0:
    print(1)
    exit()

# sep = 0
# for i in range(n-1):
#     if a[i:i+2] == "01" or a[i:i+2] == "10":
#         sep += 1
#
m = 998244353
#
# def fac(n):
#     if n == 0: return 1
#     return n * fac(n-1)
#
# def C(n, k):
#     return fac(n)//(fac(n-k)*fac(k))
#
# ans = 2;
# for i in range(1, sep+1, 2):
#     ans += C(n-1, i) % m
#
# print(int(ans % m))

a = a.replace("10", "1,0")
a = a.split(",")
multi = [(len(i)+1)%m for i in a]
ans = 1
for i in multi:
    ans *= i
    ans %= m

print(ans)