/* -*- coding: utf-8 -*-
 *
 * 3456.cc:  No.3456 Common Difference is D - yukicoder
 */

#include<cstdio>
#include<map>
#include<algorithm>

using namespace std;

/* constant */

const int MAX_N = 100000;

/* typedef */

using ll = long long;
using mii = map<int,int>;

/* global variables */

int as[MAX_N];

/* subroutines */

/* main */

int main() {
  int n, d;
  scanf("%d%d", &n, &d);
  for (int i = 0; i < n; i++) scanf("%d", as + i);

  mii lacs, racs;
  for (int i = 0; i < n; i++) racs[as[i]]++;

  ll sum = 0;
  for (int i = 0; i < n; i++) {
    auto mit = racs.find(as[i]);
    if (--(mit->second) == 0) racs.erase(mit);
    
    auto lmit = lacs.find(as[i] - d);
    if (lmit != lacs.end()) {
      auto rmit = racs.find(as[i] + d);
      if (rmit != racs.end())
	sum += (ll)lmit->second * rmit->second;
    }

    lacs[as[i]]++;
  }

  printf("%ld\n", sum);

  return 0;
}