#include "stdio.h"

#include "stdlib.h"

#define maxn 16

typedef long long LL;

LL dp[maxn][1 << maxn];

LL s[maxn];

int main() {

int n, k;

scanf("%d %d", &n, &k);

for (int i = 0; i < n; i++)

scanf("%lld", s + i);

for (int i = 0; i < n; i++)

dp[i][1 << (n - i - 1)] = 1;

int new_state;

for (int state = 1; state < (1 << n); state++)

for (int i = 0; i < n; i++) {

if (state & (1 << (n - i - 1))) continue;

new_state = state | (1 << (n - i - 1));

for (int j = 0; j < n; j++) {

if (!(state & (1 << (n - j - 1)))) continue;

if (abs(s[i] - s[j]) <= k) continue;

dp[i][new_state] += dp[j][state];

}

}

LL result = 0;

for (int i = 0; i < n; i++)

result += dp[i][(1 << n) - 1];

printf ("%lld", result);

return 0;

}