#include<iostream>
#include<cstdio>
#include<algorithm>
#include<map>
using namespace std;
int n,c;
int a[200010];
map<int,int>sum;
int ans=0;
int main(){
	cin>>n>>c;
	for(int i=1;i<=n;++i){
		cin>>a[i];
		sum[a[i]]++;
	}
	for(int i=1;i<=n;++i){
		ans+=sum[a[i]+c];
	}
	cout<<ans<<endl;
	return 0;
}