An integer $$$ n $$$ and an array $$$ a $$$ of length $$$ 2n $$$ are given. Consider splitting the array $$$ a $$$ into two subsequences $$$ p $$$ and $$$ q $$$ of length $$$ n $$$. We sort $$$ p $$$ non-decreasing, and $$$ q $$$ non-increasing, and we get the sequences $$$ x $$$ and $$$ y $$$, respectively. Then we call the cost of the partition $$$ f(p, q) = \sum_{i = 1}^n |x_i - y_i|$$$.
Calculate the sum of $$$f(p, q)$$$ over all correct partitions of $$$ a $$$. Since this number can be truly huge, you need to calculate it modulo $$$998244353$$$. Ogneslav awaits his fiery deeds, so he asks to solve this problem for him.
The first line contains a single integer $$$n$$$ ($$$1 \leq n \leq 150\,000$$$).
The second line contains $$$ 2n $$$ integer numbers $$$a_1, a_2, \ldots, a_{2n}$$$ ($$$1 \leq a_i \leq 10^9$$$) — array elements.
Print one integer number — the answer to the problem modulo $$$998244353$$$.
1 1 4
6
2 2 1 2 1
12
3 2 2 2 2 2 2
0
Two partitions of an array are considered different if the sets of indices of elements included in the subsequence $$$ p $$$ differ.
In the first example, there are two correct partitions of the array $$$ a $$$:
In the second example, there are six valid partitions of the $$$ a $$$ array:
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