#include<bits/stdc++.h>
#define MAXN 1000001
using namespace std;
int n,d,a[MAXN];
long long ans;
int main(){
	cin>>n>>d;
	for(int i=1;i<=n;i++){
		cin>>a[i];
		int k=i-1;
		while(k>1&&a[k]>=a[i]-d){
			ans++;
			k--;
		}
	}
	cout<<ans<<endl;
	return 0;
}