#include <iostream>
#include <algorithm>
#include <cstring>
#include <sstream>
#include <map>
#include <queue>
#include <set>
#include <vector>
#include <stack>
#include <cstdio>
#include <cmath>
#define mk make_pair
#define pb push_back
#define printf printf_s
#define scanf scanf_s
using namespace std;
typedef long long int ll;
typedef pair<ll, ll> pos;
const ll MOD = 1000000007, N = 20010, dx[4] = { -1,1,0,0 }, dy[4] = { 0,0,-1,1 }, MIN = -72340172838076673, MAX = 72340172838076673;

ll mn(ll a, ll b) {
	if (a == -1)return b;
	if (b == -1)return a;
	return min(a, b);
}
ll gcd(ll v1, ll v2) {
	if (v1 == 0)return v2; if (v2 == 0)return v1; if (v2 > v1)return gcd(v2%v1, v1); return gcd(v1%v2, v2);
}

ll pw(ll v1, ll v2) {
	ll v3 = 1;
	while (v2 > 0) {
		if (v2 % 2)v3 = (v3*v1) % MOD;
		v1 = (v1*v1) % MOD;
		v2 /= 2;
	}
	return v3;
}

struct ab {
	ll a, b;
	bool operator<(const ab& right) const {
		return right.b*a - right.a*b < 0;
	}
};

ll n,k,a[N],mi,ans=1,ft[N],rv[N];

int main() {
	cin >> n >> k;
	ft[0] = 1; rv[0] = 1;
	for (int i = 1; i < N; i++) { 
		ft[i] = (ft[i - 1] * i) % MOD; 
		rv[i] = pw(ft[i], MOD - 2); 
	}
	for (int i = 1; i <= n; i++)cin >> a[i];
	sort(a, a + n);
	mi = upper_bound(a + 1, a + n + 1, k / 2) - a;
	if (n - mi + 1 > mi-1) {
		cout << 0 << endl;
	}
	else {
		for (int i = n,i2=0; i >=mi; i++,i2--) {
			ll v1 = upper_bound(a + 1, a + n + 1, k - a[i]) - a - 1;
			if (v1 <= i2)ans = 0;
			else ans *= (v1 - i2);
			ans %= MOD;
		}
		ll vv = 2 * mi - n - 2;
		ans *= rv[vv / 2]; ans %= MOD;
		for (int i = 2; i <= vv; i += 2) {
			ll v1 = (ft[i] * rv[2]) % MOD;
			v1 = (v1* rv[i - 2]) % MOD;
			ans = (ans*v1) % MOD;
		}
		cout << ans << endl;
	}
	return 0;
}