atcoder#ABC221E. [ABC221E] LEQ

[ABC221E] LEQ

Score : 500500 points

Problem Statement

Given is a sequence of NN integers: A=(A1,A2,,AN)A = (A_1, A_2, \dots, A_N).

Find the number of (not necessarily contiguous) subsequences A=(A1,A2,,Ak)A'=(A'_1,A'_2,\ldots,A'_k) of length at least 22 that satisfy the following condition:

  • A1AkA'_1 \leq A'_k.

Since the count can be enormous, print it modulo 998244353998244353.

Here, two subsequences are distinguished when they originate from different sets of indices, even if they are the same as sequences.

Constraints

  • 2N3×1052 \leq N \leq 3 \times 10^5
  • 1Ai1091 \leq A_i \leq 10^9
  • All values in input are integers.

Input

Input is given from Standard Input in the following format:

NN

A1A_1 A2A_2 \ldots ANA_N

Output

Print the number of (not necessarily contiguous) subsequences A=(A1,A2,,Ak)A'=(A'_1,A'_2,\ldots,A'_k) of length at least 22 that satisfy the condition in Problem Statement.

3
1 2 1
3

A=(1,2,1)A=(1,2,1) has four (not necessarily contiguous) subsequences of length at least 22: (1,2)(1,2), (1,1)(1,1), (2,1)(2,1), (1,2,1)(1,2,1).

Three of them, (1,2)(1,2), (1,1)(1,1), (1,2,1)(1,2,1), satisfy the condition in Problem Statement.

3
1 2 2
4

Note that two subsequences are distinguished when they originate from different sets of indices, even if they are the same as sequences.

In this Sample, there are four subsequences, (1,2)(1,2), (1,2)(1,2), (2,2)(2,2), (1,2,2)(1,2,2), that satisfy the condition.

3
3 2 1
0

There may be no subsequence that satisfies the condition.

10
198495780 28463047 859606611 212983738 946249513 789612890 782044670 700201033 367981604 302538501
830