时间限制：C/C++/Rust/Pascal 3秒，其他语言6秒
空间限制：C/C++/Rust/Pascal 512 M，其他语言1024 M
64bit IO Format: %lld
空间限制：C/C++/Rust/Pascal 512 M，其他语言1024 M
64bit IO Format: %lld
题目描述
lndjy has his own unique interest in numbers. Today he came up with a multiset 
consists of 
non-negative integers which are not greater than . More precisely, he has given a sequence of non-negative integers 
, representing that for each integer 
, the number of elements in equal to 
is exactly 
. It is guaranteed that 
.
lndjy also showed his great interest in Combinatorics. So he wants to make sequences with. Let the set of all different sequences which has exactly the same elements as be 
. It's easy to prove that 
.
What's more, lndjy loves subsegments and the mex. He defined a function)
on all subsegments of any given sequence 
as
%20%3D%20%5Coperatorname%7Bmex%7D%5C%7Bb_l%2C%20b_%7Bl%2B1%7D%2C%20%5Cdots%2C%20b_r%5C%7D)
where
is the smallest non-negative integer which is not present in the multiset 
. For example, 
, 
and 
.
Finally, he wants you to calculate the value of
%20%5Cbmod%20998244353)
lndjy also showed his great interest in Combinatorics. So he wants to make sequences with
What's more, lndjy loves subsegments and the mex. He defined a function
where
Finally, he wants you to calculate the value of
输入描述:
The first line contains one integer).
The second line containsintegers
).
输出描述:
Print a single integer, equals to