#include<bits/stdc++.h>
using namespace std;
const int N=200005;
int a[N],ans;
int main(){
int n,m;
scanf("%d%d",&n,&m);
for(int i=1;i<=n;i++){
scanf("%d",a+i);
}
sort(a+1,a+n+1);
for(int i=1;i<=n;i++){
ans+=upper_bound(a+1,a+n+1,a[i]+m)-lower_bound(a+1,a+n+1,a[i]+m);
}
printf("%d",ans);
return 0;
}
求助大神(巨佬),第三个点死活过不去,本地测数据都无法全部输入QAQ