#include <iostream>
#include <vector>
#include <map>
using namespace std;
using ll = long long;

int main(){
    int N, D;
    cin >> N >> D;
    vector<int> A(N);
    map<int, vector<int>> I;
    for (int i = 0; i < N; i++){
        cin >> A[i];
        I[A[i]].push_back(i);
    }

    ll ans = 0;
    for (int i = 0; i < N; i++){
        ll l = lower_bound(I[A[i]-D].begin(), I[A[i]-D].end(), i)-I[A[i]-D].begin();
        ll r = I[A[i]+D].end()-upper_bound(I[A[i]+D].begin(), I[A[i]+D].end(), i);
        ans += l*r;
    }

    cout << ans << endl;
}