#include<bits/stdc++.h>
using namespace std;
int n[200010];
int BS1(int number[],int n,int x){
	int low=0,high=n-1,mid;
        int result=-1;
        while(low<=high){
            mid=low+(high-low)/2;
            if(x<=number[mid]){
                result=mid;
                high=mid-1;
            }else {
                low=mid+1;
        	}
    }
    return result;
}
int BS2(int number[],int n,int x){
	int low=0,high=n-1,mid;
	int result=-1;
	while(low<=high){
		mid=low+(high-low)/2;
		if(x<number[mid]){
			result=mid;
			high=mid-1; 
        }else {
           low=mid+1;
    	}
	}
	return result;
}
int main(){
	int N,c;
	cin>>N>>c;
	for(int i=0;i<N;i++){
		cin>>n[i];
	}
	sort(n,n+N);
	int sum=0;
	for(int i=0;i<N;i++){
		int t=n[i]+c;
		int ans1=BS1(n,N,t);
		int ans2=BS2(n,N,t);
		if(ans1==-1){
			if(ans2==-1){
				sum+=0;
			}
			else{
				sum+=0;
			}
		} 
		else{
			if(ans2==-1){
				sum+=(N-ans1);
			}
			else{
				sum+=(ans2-ans1);
			}
		}
	}
	cout<<sum;
	return 0;
}