#include <bits/stdc++.h>
using namespace std;

#define For(i, a, b) for(int i = (a); i < (b); i++)
#define rep(i, n) For(i, 0, n)
#define rFor(i, a, b) for(int i = (a); i >= (b); i--)
#define ALL(v) (v).begin(), (v).end()
#define rALL(v) (v).rbegin(), (v).rend()
#define SZ(v) ((int)(v).size())

using lint = long long;
using ld = long double;

const int INF = 1001001001;
const lint LINF = 1000000000000000000;
// 真上から反時計回り
const int di[] = {-1, 0, 1, 0};
const int dj[] = {0, -1, 0, 1};
const int di8[] = {-1, -1, 0, 1, 1, 1, 0, -1};
const int dj8[] = {0, -1, -1, -1, 0, 1, 1, 1};

struct SetupIo {
    SetupIo() {
        ios::sync_with_stdio(false); cin.tie(nullptr);
        cout << fixed << setprecision(15);
        cerr << fixed << setprecision(15);
    }
} setupio;

namespace tatsumr {

template <class T>
bool chmin(T &a, const T &b) {
    return a > b ? a = b, 1 : 0;
}
template <class T>
bool chmax(T &a, const T &b) {
    return a < b ? a = b, 1 : 0; 
}
template <class T>
T mypow(T a, T b) {
    T res = 1;
    while (b) {
        if (b & 1) { res *= a; }
        a *= a; b >>= 1;
    }
    return res;
}
template <class T>
T modpow(T a, T b, T mod) {
    T res = 1;
    while (b) {
        if (b & 1) { res = (res * a) % mod; }
        a = (a * a) % mod; b >>= 1;
    }
    return res;
}

} // namespace tatsumr

using namespace tatsumr;

int main() {
    lint N, D;
    cin >> N >> D;
    vector<lint> A(N);
    rep(i, N) {
        cin >> A[i];
    }
    map<lint, vector<int>> mp;
    rep(i, N) {
        mp[A[i]].emplace_back(i);
    }
    lint ans = 0;
    // 真ん中全探索
    For(i, 1, N) {
        lint x = A[i] - D;
        lint cx = 0;
        if (mp.count(x)) {
            cx = upper_bound(ALL(mp[x]), i) - mp[x].begin();
        }

        lint y = A[i] + D;
        lint cy = 0;
        if (mp.count(y)) {
            cy = (lint)(SZ(mp[y])) - (lint)(upper_bound(ALL(mp[y]), i) - mp[y].begin());
        }

        ans += cx * cy;
    }

    cout << ans << "\n";
}