#include <iostream>
#include <algorithm>
using namespace std;
typedef long long ll;
ll a[200010],b[200010],ans = 1,mod = 10000000007;
int main(){
	int i,n,k;
	cin >> n >> k;
	for(i=0;i<n;i++){
		cin >> a[i];
	}
	sort(a,a + n);
	int j = -1;
	for(i=n-1;i>=0;i--){
		while(a[j+1]+a[i]<=k && j+1<n) j++;
		b[i] = min(i - 1,j) + 1;
	}
	j = 0;
	for(i=n-1;i>=n/2;i--){
		if(b[i] - j<=0){
			ans = 0;
			break;
		}
		(ans *= (b[i] - j)) %= mod;
		j++;
	}
	cout << ans << endl;
}