#include <bits/stdc++.h>
#include <atcoder/all>
#include <iostream>
#include <cmath>
using namespace std;
using namespace atcoder;
using ll = long long;
using lb = long double;
using P = pair<ll, ll>;
using T = tuple<ll, ll, ll>;
using vll = vector<ll>;
using vb = vector<bool>;
using vvll = vector<vector<ll>>;
using vP = vector<P>;
using Graph = vector<vector<ll>>;
using WGraph = vector<vector<pair<ll, ll>>>; // コスト、頂点番号の順
using mint = modint998244353;
//using mint = long double;
#define rep0(i, n) for (ll i = 0; i < (ll)(n); i++)
#define rep1(i, n) for (ll i = 1; i <= (ll)(n); i++)
mt19937_64 rng(58);
long double PI = 3.14159265358979;
const ll LLMAX = 9223372036854775807;
const ll INF = 1e18;
vector<ll> di = {-1, 0, 1, 0}; // 上左下右
vector<ll> dj = {0, -1, 0, 1};
template<typename T> inline bool chmax(T &a, T b) { return ((a < b) ? (a = b, true) : (false)); }
template<typename T> inline bool chmin(T &a, T b) { return ((a > b) ? (a = b, true) : (false)); }

int main() {
    ll n, d;
    cin >> n >> d;
    vll a(n);
    rep0 (i, n) cin >> a[i];

    map<ll, ll> mp;    
    ll ans = 0;
    rep0 (i, a.size()) {
        mp[a[i]]++;
        ans += mp[a[i] - d] * mp[a[i] - 2 * d];
    }
    cout << ans << endl;
    return 0;
}