#include <cstdio>
#include <iostream>

using namespace std;

int a[200100];

int main()
{
	int N, C;
	scanf_s("%d%d", &N, &C);
	for (int i = 0; i < N; i++)
	{
		scanf_s("%d",&a[i]);
	}
	int ans = 0;
	for (int i = 0; i < N; i++)
	{
		for (int j = 0; j < N; j++)
		{
			if (a[i] - a[j] == C) ans++;
		}
	}
	printf("%d", ans);
	return 0;
}