#include <bits/stdc++.h>
#define int long long
using namespace std;

int n , k;
int a[20];
int res ;
int vis[20];
bool stat[20];

void dfs(int head, int cnt)
{
	if (cnt == n) {
		res++;
		return;
	}
	for (int i = 1; i <= n; i++) {
		if ((!stat[i]) && abs(a[i] - vis[cnt]) > k) {
			vis[cnt + 1] = a[i];
			stat[i] = true;
			dfs(head, cnt + 1);
			vis[cnt + 1] = 0;
			stat[i] = false;
		}
	}
	return;
}

#undef int
int main()
#define int long long
{
//	ios::sync_with_stdio(false), cin.tie(nullptr);
    freopen("mengbi.in","r",stdin);
    freopen("mengbi.out","w",stdout);
    cin >> n >>k;
	for (int i = 1; i <= n; i++)
		cin >> a[i];
	for (int i = 1; i <= n; i++) {
		memset(vis, 0, sizeof(vis));
		memset(stat, 0, sizeof(stat));
		vis[1] = a[i];
		stat[i] = true;
		dfs(i, 1);
	}
	cout << res;

	exit(0);
}