You need to log into a mysterious system, but you realize you've forgotten your password. The system does not support resetting password, so the only way to log in is to keep trying.
Fortunately, you still remember some information about the password:
Firstly, you are sure that the length of the password is $$$n$$$ .
Then the information you remember can be described by a string $$$s$$$ of length $$$n$$$.
let $$$s_i$$$ represent the $$$i$$$-th character of $$$s$$$ :
It's guaranteed that the string $$$s$$$ only contains uppercase letters, lowercase letters, digital characters, and question marks '?'.
In addition, the system also has several requirements for passwords:
Now you want to know, how many possible passwords are there? A possible password should fits both your memory and the system's requirements, and it's guaranteed that there exists at least one possible password.
You know that this answer will be very large, so you just need to calculate the result modulo $$$998244353$$$ .
Please note the unusual memory limit.
The first line contains a single integer $$$n\ (3\le n \le 10^5)$$$ , representing the length of the password .
The second line contains a string $$$s$$$ with length $$$n$$$. It's guaranteed that the string $$$s$$$ only contains uppercase letters, lowercase letters, digital characters, and question marks '?'.
It's guaranteed that there exists at least one possible password.
output a single line containing a single integer, representing the answer modulo $$$998244353$$$.
4 a?0B
86
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