import sys
input = sys.stdin.readline

MOD = 998244353

def solve():
    N = int(input())
    A = input().strip()
    
    if '0' not in A or '1' not in A:
        print(1)
        return
    
    pz = A.index('0')                # first '0' position
    lo = N - 1 - A[::-1].index('1') # last '1' position
    
    if pz > lo:
        print(1)
        return
    
    dp = [1, 1]
    
    for j in range(pz, lo):
        new_dp = [0, 0]
        new_dp[0] = (new_dp[0] + dp[0]) % MOD     # 0→0
        new_dp[1] = (new_dp[1] + dp[0]) % MOD     # 0→1
        new_dp[1] = (new_dp[1] + dp[1]) % MOD     # 1→1
        if A[j] == '1' and A[j+1] == '0':         # 1→0 only if A has "10" here
            new_dp[0] = (new_dp[0] + dp[1]) % MOD
        dp = new_dp
    
    print((dp[0] + dp[1]) % MOD)

solve()