问题 I: We Love Strings

内存限制：256 MB 时间限制：3 S 标准输入输出

题目类型：传统评测方式：文本比较上传者：

提交：6 通过：3

链接：https://ac.nowcoder.com/acm/contest/57361/I
来源：牛客网
We have n strings

s_i

which only contain

01?\texttt{01?}

?\texttt{?}

means it can match either

0

1

.
You need to find how many

01

strings are there which matches at least one of these strings.

The first line contains one integer

n(1≤n≤400)n(1\leq n\leq 400)

.
The next

n

lines, the

i

-th line contains a string

si(1≤∑∣si∣≤400)s_i(1\leq \sum|s_i|\leq 400)

Output the answer modulo

998244353

in one line.

3
10?
?0?
?11