#include<bits/stdc++.h>
#define int long long
const int N = 20;
using namespace std;
int n,k;
int a[N];
bool vs [N];
int ans = 0;
void dfs (int x,int cnt) {
	if (cnt >= n) {
		ans++;
		return; 
	}
	for (int i = 1; i <= n; ++i) {
		if (vs[i]) continue;
		if (abs(a[i] - a[x]) <= k) continue;
		if (!vs[i] && abs(a[i] - a[x]) > k) {
			vs[i] = true;
			dfs(i,cnt + 1);
			vs[i] = false;
		}
	}
	return;
}
signed main() {
	freopen("mengbi.in","r",stdin);
	freopen("mengbi.out","w",stdout);
    cin >> n >> k;
    for (int i = 1; i <= n; ++i) cin >> a[i];
    memset(vs,false,sizeof(vs));
    for (int i = 1; i <= n; ++i) {
    	memset(vs,false,sizeof(vs));
    	vs[i] = true;
    	dfs(i,1);
    }
    cout << ans;
    return 0;
}