#include<cstdio>
#include<iostream>
#include<algorithm>
using namespace std;
int n,m,a[1000010],b[1000010]={0};
int s(int k)
{
	int left=0;
	int right=n-1;
	
	while(left<=right){
		int mid=(left+right)/2;
		if(a[mid]==k) return 1;
		else if(a[mid]>k) right=mid-1;
		else if(a[mid]<k) left=mid+1;
	}
	return 0;
}

int main()
{
	int sum=0;
	scanf("%d %d",&n,&m);
	for(int i=0;i<n;i++)
	{
	scanf("%d",&a[i]);
		b[a[i]]++;
   }
   sort(a,a+n);
	for(int i=0;i<n;i++)
	{
		if(s(a[i]-m))
		for(int t=0;t<b[a[i]-m];t++)
			sum++;
	 } 
	printf("%d",sum);
	
return 0;
 }