#include <cstdio>
#include <algorithm>
using namespace std;
const int maxn = 10+5;
FILE *fin, *fout;
int n, k, d[maxn], ans=0;
int abs(int a) { return a<0?-a:a; }
int main() {
	fin = fopen("round.in", "r");
	fout = fopen("round.out", "w");
	fscanf(fin, "%d%d", &n, &k);
	for(int i = 0; i < n; i++) fscanf(fin, "%d", &d[i]);
	sort(d, d+n);
	do {
		bool flag = true;
		for(int i = 0; i < n; i++) if(abs(d[i]-d[(i+1)%n]) > k) { flag = false; break; }
		if(flag) ans++;
		/*if(flag) {
			for(int i = 0; i < n; i++) printf("%d ", d[i]);
			printf("\n");
		}*/
	}while(next_permutation(d, d+n));
	fprintf(fout, "%d\n", ans/n);
	return 0;
}