#include <bits/stdc++.h>

using namespace std;

using ll = long long;

const ll MOD = 1000000007;

ll modpow(ll x, ll n, ll mod = MOD) {
	ll res = 1;
	while (n > 0) {
		if (n & 1) res = res * x % mod;
		x = x * x % mod;
		n >>= 1;
	}
	return res;
}

ll calc(int num, vector<ll>& f, vector<ll>& fi) {
	ll res = 1;
	for (int i = num * 2; i >= 2; i -= 2) {
		ll tmp = i;
		tmp = tmp * (i-1) % MOD * fi[2] % MOD;
		(res *= tmp) %= MOD;
	}
	(res *= fi[num]) %= MOD;
	return res;
}

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int n;
	ll K;
	cin >> n >> K;
	vector<ll> a(n);
	for (int i = 0; i < n; i++) cin >> a[i];
	sort(a.begin(), a.end(), greater<>());

	bool flag = true;
	for (int i = 0; i < n; i++) {
		int j = n - 1 - i;
		if (j < i) break;
		if (a[i] + a[j] > K) {
			flag = false;
			break;
		}
	}

	if (!flag) {
		cout << 0 << endl;
		return 0;
	}

	vector<ll> f(2 * n + 1, 1), fi(2 * n + 1, 1);
	for (int i = 1; i <= 2*n; i++) {
		f[i] = f[i-1]*i%MOD;
	}
	fi[2*n] = modpow(f[2*n], MOD - 2, MOD);
	for (int i = 2 * n; i > 0; i--) {
		fi[i-1] = fi[i]*i%MOD;
	}

	ll ans = 1;
	for (int i = 0, j = n - 1; i < n; i++) {
		while (j > i + 1) {
			if (a[j-1]+a[i]<=K) j--;
			else break;
		}

		if (j == i + 1) {
			int num = (n - 2 * i) / 2;
			if (num < 0) break;
			(ans *= calc(num, f, fi)) %= MOD;
			break;
		}

		int hoge = n - j - i;
		(ans *= hoge) %= MOD;
	}
	cout << ans << endl;
	return 0;
}