#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
vector<int> num;

int main() {
	int n, c;
	cin >> n >> c;

	for (int i = 0; i < n; i++) {
		int tem;
		cin >> tem;
		num.push_back(tem);
	}

	sort(num.begin(), num.end());
	vector<int>::iterator a = num.begin();
	int dec = *a + c, ssum = 0, tem;

	while (dec <= num[n - 1]) {
		dec = *a + c;
		tem = upper_bound(a, num.end(), dec) - lower_bound(a, num.end(), dec);
		ssum += tem;
		a++;
	}

	cout << ssum;
}