#include <bits/stdc++.h>
using namespace std;
long long a[1000005];
int main() {
	long long n, c,sum=0;
	cin >> n >> c ;
	for (long long i = 1; i <= n; i++) {
		cin >> a[i];
	}
	for (long long i = 1; i <= n; i++) {
		for (long long j = i + 1; j <= n; j++) {
			if(abs(a[i]-a[j])==c){
				sum++;
			}
		}
	}
	cout << sum;
	return 0;
}