CR08C1P5 - SREDNJI

no tags 

Consider a sequence A of integers, containing N integers between 1 and N. Each integer appears exactly once in the sequence.

A subsequence of A is a sequence obtained by removing some (possibly none) numbers from the beginning of A, and then from the end of A.

Calculate how many different subsequences of A of odd length have their median equal to B. The median of a sequence is the element in the middle of the sequence after it is sorted. For example, the median of the sequence {5, 1, 3} is 3.

Input

The first line contains two integers, N (1 ≤ N ≤ 100000) and B (1 ≤ B ≤ N).

The second line contains N integers separated by spaces, the elements of sequence A.

Output

Output the number of subsequences of A whose median is B.

Example

Input:
5 4
1 2 3 4 5 

Output:
2
Input:
6 3
1 2 4 5 6 3 

Output:
1
Input:
7 4
5 7 2 4 3 1 6 

Output:
4

In the third example, the four subsequences of A with median 4 are {4}, {7, 2, 4}, {5, 7, 2, 4, 3} and {5, 7, 2, 4, 3, 1, 6}.



Added by:Ahmed Salem [mrtempo]
Date:2015-01-23
Time limit:1s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ASM64 JS-MONKEY
Resource:COCI 2007/2008 #1 (http://hsin.hr/coci/archive/2007_2008/contest1_tasks.pdf)