#include <bits/stdc++.h>
using namespace std;
long long n,c,a[1000000],sum;
int read(){
	int x=0;
	char c=getchar();
	while(c<'0'||c>'9') c=getchar();
	while(c>='0'&&c<='9'){
		x=x*10+c-'0';
		c=getchar();
	}
	return x;
}
int main(){
	n=read();
	c=read();
	for(int i=0;i<n;i++){
		a[i]=read();
	}
	for(int i=0;i<n;i++){
		for(int j=i+1;j<n;j++){
			if(abs(a[i]-a[j])==c){
				sum++;
			}
		}
	}
	cout<<sum;
}