#arc154e. [arc154_e]Reverse and Inversion

[arc154_e]Reverse and Inversion

Problem Statement

For a permutation Q=(Q1,Q2,dots,QN)Q=(Q_1,Q_2,\\dots,Q_N) of (1,2,dots,N)(1,2,\\dots,N), let f(Q)f(Q) be the following value:

the sum of jij-i over all pairs of integers (i,j)(i,j) such that 1lei<jleN1 \\le i < j \\le N and Qi>QjQ_i > Q_j.

You are given a permutation P=(P1,P2,dots,PN)P=(P_1,P_2,\\dots,P_N) of (1,2,dots,N)(1,2,\\dots,N).

Let us repeat the following operation MM times.

  • Choose a pair of integers (i,j)(i,j) such that 1leilejleN1 \\le i \\le j \\le N. Reverse Pi,Pi+1,dots,PjP_i,P_{i+1},\\dots,P_j. Formally, replace the values of Pi,Pi+1,dots,PjP_i,P_{i+1},\\dots,P_j with Pj,Pj1,dots,PiP_j,P_{j-1},\\dots,P_i simultaneously.

There are left(fracN(N+1)2right)M\\left(\\frac{N(N+1)}{2}\\right)^{M} ways to repeat the operation. Assume that we have computed f(P)f(P) for all those ways.

Find the sum of these left(fracN(N+1)2right)M\\left(\\frac{N(N+1)}{2}\\right)^{M} values, modulo 998244353998244353.

Constraints

  • 1leN,Mle2times1051 \\le N,M \\le 2 \\times 10^5
  • (P1,P2,dots,PN)(P_1,P_2,\\dots,P_N) is a permutation of (1,2,dots,N)(1,2,\\dots,N).

Input

The input is given from Standard Input in the following format:

NN MM P1P_1 P2P_2 dots\\dots PNP_N

Output

Print a single line containing the answer.


Sample Input 1

2 1
1 2

Sample Output 1

1

There are three ways to perform the operation, as follows.

  • Choose (i,j)=(1,1)(i,j)=(1,1), making P=(1,2)P=(1,2), where f(P)=0f(P)=0.
  • Choose (i,j)=(1,2)(i,j)=(1,2), making P=(2,1)P=(2,1), where f(P)=1f(P)=1.
  • Choose (i,j)=(2,2)(i,j)=(2,2), making P=(1,2)P=(1,2), where f(P)=0f(P)=0.

Thus, the answer is 0+1+0=10+1+0=1.


Sample Input 2

3 2
3 2 1

Sample Output 2

90

Sample Input 3

10 2023
5 8 1 9 3 10 4 7 2 6

Sample Output 3

543960046