MOD = 998244353
N = int(input())
S = input()

dp = [[0] * 2 for _ in range(N+1)]
dp[0][0] = 1
for i, c in enumerate(S):
    if c == '0':
        dp[i+1][0] = dp[i][0] + dp[i][1]
        dp[i+1][0] %= MOD
        dp[i+1][1] = dp[i][1]
    else:
        dp[i+1][0] = 0
        dp[i+1][1] = dp[i][0] + dp[i][1] * 2
        dp[i+1][1] %= MOD

ans = dp[N][1]
print(ans)