import sys
input = sys.stdin.readline
MOD = 998244353
N = int(input())
S = input().strip()
dp = [[0 for _ in range(2)] for _ in range(N+1)]
dp[0][0] = 1
for i in range(N):
    if S[i]=="1":
        dp[i+1][0] += dp[i][0] + dp[i][1]
        dp[i+1][0] %= MOD
        dp[i+1][1] += dp[i][0] + dp[i][1]
        dp[i+1][1] %= MOD
    else:
        dp[i+1][0] += dp[i][0] + dp[i][1]
        dp[i+1][0] %= MOD
        dp[i+1][1] += dp[i][1]
        dp[i+1][1] %= MOD
print(dp[N][1])