#include<bits/stdc++.h>
using namespace std;
int n,c;
const int maxn=2e5+7;
int a[maxn];
int ans=0;
int bina_lower(int s,int ce){ //查找左区间
    int l=s,r=n;
    int mid;
    while(l<=r){
        mid=l+r>>1;
        if(a[mid]-a[s]>=ce){
            r=mid-1;
        }
        else{
            l=mid+1;
        }
    }
    return l;
}
int bina_upper(int s,int ce){//查找右区间
    int l=s,r=n;
    int mid;
    while(l<=r){
        mid=l+r>>1;
        if(a[mid]-a[s]>ce){
            r=mid-1;
        }
        else{
            l=mid+1;
        }
    }
    return l;
}
int main()
{
    cin>>n>>c;
    for(int i=1;i<=n;i++){
        cin>>a[i];
    }
    sort(a+1,a+1+n);
    for(int i=1;i<=n;i++){
        if(a[n]-a[i]<c){
            break;
        }
        ans+=bina_upper(i,c)-bina_lower(i,c);
    }
    cout<<ans;
    return 0;
}