#D11308. Median on Segments (Permutations Edition)
Median on Segments (Permutations Edition)
Median on Segments (Permutations Edition)
You are given a permutation p_1, p_2, ..., 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 ≤ l ≤ r ≤ n) such that the value of the median of p_l, p_{l+1}, ..., 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 ≤ l ≤ r ≤ n) such that the value of the median of p_l, p_{l+1}, ..., p_r is exactly the given number m.
Input
The first line contains integers n and m (1 ≤ n ≤ 2⋅10^5, 1 ≤ m ≤ n) — the length of the given sequence and the required value of the median.
The second line contains a permutation p_1, p_2, ..., p_n (1 ≤ p_i ≤ 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).
inputFormat
Input
The first line contains integers n and m (1 ≤ n ≤ 2⋅10^5, 1 ≤ m ≤ n) — the length of the given sequence and the required value of the median.
The second line contains a permutation p_1, p_2, ..., p_n (1 ≤ p_i ≤ n). Each integer between 1 and n occurs in p exactly once.
outputFormat
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).
样例
5 4
2 4 5 3 1
4