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

int main(){
	using ll=long long;
	int n,d;
	cin>>n>>d;
	vector<int> a(n);
	map<int,vector<int>> mp;
	for (int i=0;i<n;i++){
		cin>>a[i];
		mp[a[i]].push_back(i);
	}
	auto f=[&](int x,int r){
		if (!mp.count(x)) return 0LL;
		ll ret=lower_bound(mp[x].begin(),mp[x].end(),r)-mp[x].begin();
		return ret;
	};
	ll ans=0;
	for (int i=0;i<n;i++){
		ll c0=f(a[i]-d,i)-f(a[i]-d,0);
		ll c1=f(a[i]+d,n)-f(a[i]+d,i+1);
		ans+=c0*c1;
	}
	cout<<ans<<endl;
}