Please subscribe to the official Codeforces channel in Telegram via the link: https://t.me/codeforces_official.
×

Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ACM-ICPC mode for virtual contests.
If you've seen these problems, a virtual contest is not for you - solve these problems in the archive.
If you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.
Never use someone else's code, read the tutorials or communicate with other person during a virtual contest.

No tag edit access

E1. Median on Segments (Permutations Edition)

time limit per test

3 secondsmemory limit per test

256 megabytesinput

standard inputoutput

standard outputYou are given a permutation $$$p_1, p_2, \dots, p_n$$$. A permutation of length $$$n$$$ is a sequence such that each integer between $$$1$$$ and $$$n$$$ occurs exactly once in the sequence.

Find the number of pairs of indices $$$(l, r)$$$ ($$$1 \le l \le r \le n$$$) such that the value of the median of $$$p_l, p_{l+1}, \dots, p_r$$$ is exactly the given number $$$m$$$.

The median of a sequence is the value of the element which is in the middle of the sequence after sorting it in non-decreasing order. If the length of the sequence is even, the left of two middle elements is used.

For example, if $$$a=[4, 2, 7, 5]$$$ then its median is $$$4$$$ since after sorting the sequence, it will look like $$$[2, 4, 5, 7]$$$ and the left of two middle elements is equal to $$$4$$$. The median of $$$[7, 1, 2, 9, 6]$$$ equals $$$6$$$ since after sorting, the value $$$6$$$ will be in the middle of the sequence.

Write a program to find the number of pairs of indices $$$(l, r)$$$ ($$$1 \le l \le r \le n$$$) such that the value of the median of $$$p_l, p_{l+1}, \dots, p_r$$$ is exactly the given number $$$m$$$.

Input

The first line contains integers $$$n$$$ and $$$m$$$ ($$$1 \le n \le 2\cdot10^5$$$, $$$1 \le m \le n$$$) — the length of the given sequence and the required value of the median.

The second line contains a permutation $$$p_1, p_2, \dots, p_n$$$ ($$$1 \le p_i \le n$$$). Each integer between $$$1$$$ and $$$n$$$ occurs in $$$p$$$ exactly once.

Output

Print the required number.

Examples

Input

5 4

2 4 5 3 1

Output

4

Input

5 5

1 2 3 4 5

Output

1

Input

15 8

1 15 2 14 3 13 4 8 12 5 11 6 10 7 9

Output

48

Note

In the first example, the suitable pairs of indices are: $$$(1, 3)$$$, $$$(2, 2)$$$, $$$(2, 3)$$$ and $$$(2, 4)$$$.

Codeforces (c) Copyright 2010-2018 Mike Mirzayanov

The only programming contests Web 2.0 platform

Server time: Dec/18/2018 15:15:25 (f1).

Desktop version, switch to mobile version.

Supported by

User lists

Name |
---|