#D4601. Median on Segments (General Case Edition)
Median on Segments (General Case Edition)
Median on Segments (General Case Edition)
You are given an integer sequence a_1, a_2, ..., a_n.
Find the number of pairs of indices (l, r) (1 ≤ l ≤ r ≤ n) such that the value of median of a_l, a_{l+1}, ..., a_r is exactly the given number m.
The median of a sequence is the value of an 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 median of a_l, a_{l+1}, ..., a_r is exactly the given number m.
Input
The first line contains integers n and m (1 ≤ n,m ≤ 2⋅10^5) — the length of the given sequence and the required value of the median.
The second line contains an integer sequence a_1, a_2, ..., a_n (1 ≤ a_i ≤ 2⋅10^5).
Output
Print the required number.
Examples
Input
5 4 1 4 5 60 4
Output
8
Input
3 1 1 1 1
Output
6
Input
15 2 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
Output
97
Note
In the first example, the suitable pairs of indices are: (1, 3), (1, 4), (1, 5), (2, 2), (2, 3), (2, 5), (4, 5) and (5, 5).
inputFormat
Input
The first line contains integers n and m (1 ≤ n,m ≤ 2⋅10^5) — the length of the given sequence and the required value of the median.
The second line contains an integer sequence a_1, a_2, ..., a_n (1 ≤ a_i ≤ 2⋅10^5).
outputFormat
Output
Print the required number.
Examples
Input
5 4 1 4 5 60 4
Output
8
Input
3 1 1 1 1
Output
6
Input
15 2 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
Output
97
Note
In the first example, the suitable pairs of indices are: (1, 3), (1, 4), (1, 5), (2, 2), (2, 3), (2, 5), (4, 5) and (5, 5).
样例
15 2
1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
97
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