n = int(input())
s = input()
mod = 998244353
dp = [[0] * 2 for _ in range(n + 1)]
dp[0][0] = 1

for i in range(n):
    if s[i] == '0':
        dp[i + 1][0] += dp[i][1] + dp[i][0]
        dp[i + 1][1] += dp[i][1]
    else:
        dp[i + 1][1] += dp[i][0] + dp[i][1]
        dp[i + 1][1] += dp[i][1]
    dp[i + 1][0] %= mod
    dp[i + 1][1] %= mod

print(dp[n][1])