C

#include <bits/stdc++.h>


using namespace std;

#define int long long

const long long INF = 1e9 + 7;
const int MAXN = 200 + 10;
const int N = 1e5 + 10;

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    int n, s;
    cin >> n >> s;
    vector<int> a(n);
    for (int i = 0; i < n; ++i) {
        cin >> a[i];
    }

    int ans = 0, l = 0;
    for (int r = 0; r < n; ++r) {
        while (a[r] - a[l] > s && l <= r) {
            ++l;
        }
        ans += l;
    }
    cout << ans << '\n';
}