Problem:
Score : 600 points

Problem Statement

You are given an integer sequence of length N, a = {a_1, a_2, …, a_N}, and an integer K.

a has N(N+1)/2 non-empty contiguous subsequences, {a_l, a_{l+1}, …, a_r} (1 ≤ l ≤ r ≤ N). Among them, how many have an arithmetic mean that is greater than or equal to K?

Constraints

All input values are integers.

1 ≤ N ≤ 2 \times 10^5

1 ≤ K ≤ 10^9

1 ≤ a_i ≤ 10^9

Input

Input is given from Standard Input in the following format:

N K
a_1
a_2
:
a_N

Output

Print the number of the non-empty contiguous subsequences with an arithmetic mean that is greater than or equal to K.

Sample Input 1

3 6
7
5
7

Sample Output 1

5

All the non-empty contiguous subsequences of a are listed below:

{a_1} = {7}

{a_1, a_2} = {7, 5}

{a_1, a_2, a_3} = {7, 5, 7}

{a_2} = {5}

{a_2, a_3} = {5, 7}

{a_3} = {7}

Their means are 7, 6, 19/3, 5, 6 and 7, respectively, and five among them are 6 or greater. Note that {a_1} and {a_3} are indistinguishable by the values of their elements, but we count them individually.

Sample Input 2

1 2
1

Sample Output 2

0

Sample Input 3

7 26
10
20
30
40
30
20
10

Sample Output 3

13

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Time Limit Exceeded)

import java.util.Scanner;
public class Main {
	public static void main(String[] args){
		Main main = new Main();
		main.solveE();
	}

	private void solveE() {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		long K = sc.nextLong();
		long[] sumArr = new long[N + 1];
		sumArr[0] = 0L;
		for (int i = 1; i <= N; i++) {
			sumArr[i] = sumArr[i - 1] + sc.nextLong() - K;
		}
		long ans = 0L;
		for (int start = 0; start < N; start++) {
			for (int end = start + 1; end <= N; end++) {
				if ((sumArr[end] - sumArr[start]) >= 0) {
					ans++;
				}
			}
		}
		System.out.println(ans);
	}
}