/*
*DIV 2 C.
*LINK:
*nilabja10201992
*/
#include <bits/stdc++.h>
using namespace std;
#define inf (1<<30)
#define INF (int)1e9
#define EPS 1e-9
#define PI 3.1415926535897932384626433832795
#define MOD 1000000007
#define MAX 1000000
int n,k;
int arr[MAX];
int bsearch(int a,int i){
int l=i;
int r=n-1;
int cnt=0;
while(l<=r){
int m=(l+r)/2;
if(abs(arr[m]-a)==k)
cnt++;
if(abs(arr[m]-a)>=k)
r=m-1;
else if(abs(arr[m]-a)<k)
l=m+1;
}
l=0;
r=i;
while(l<=r){
int m=(l+r)/2;
if(abs(arr[m]-a)==k)
cnt++;
if(abs(arr[m]-a)>=k)
l=m+1;
else if(abs(arr[m]-a)<k)
r=m-1;
}
return cnt;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin>>n>>k;
for(int i=0;i<n;i++)
cin>>arr[i];
sort(arr,arr+n);
int ans=0;
for(int i=0;i<n;i++){
int a=arr[i];
ans+=bsearch(arr[i],i);
}
cout<<ans/2<<endl;
//cout<<"Execution time : "<<tick();
return 0;
}
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