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

using ll = long long;

bool chmax(auto &a, auto b) { return a < b ? a = b, 1 : 0; }
bool chmin(auto &a, auto b) { return a > b ? a = b, 1 : 0; }

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    ll N, D; cin >> N >> D;
    vector<ll> A(N);
    for (auto &&a : A) cin >> a;

    unordered_map<ll, vector<int>> mp;
    for (int i = 0; i < N; ++i) {
        mp[A[i]].emplace_back(i);
    }

    ll ans = 0;
    for (int j = 1; j < N-1; ++j) {
        ll i = lower_bound(mp[A[j] - D].begin(), mp[A[j] - D].end(), j) - mp[A[j] - D].begin();
        ll k = mp[A[j] + D].end() - upper_bound(mp[A[j] + D].begin(), mp[A[j] + D].end(), j);
        ans += i * k;
    }
    cout << ans << '\n';
}