#include<iostream>
#include<algorithm>
#include<vector>
using namespace std;
typedef long long ll;
const ll mod = 1e9+7;

int main(){
    int n, k;
    cin >> n >> k;
    vector<int> v(n);
    for(int i = 0; i < n; i++)  cin >> v[i];
    sort(v.begin(), v.end());
    ll ans = 1;
    int cur = n-1;
    for(; 2*v[cur] > k; cur--){
        int cand = lower_bound(v.begin(), v.end(), k-v[cur]+1)-v.begin()-1;
        if(k-v[cur] <= 0 || cand-(n-1-cur) <= 0){
            cout << 0 << endl;
            return 0;
        }
        ans *= (cand-(n-1-cur));
        ans %= mod;
    }
    while(cur > 0){
        ans *= cur;
        ans %= mod;
        cur -= 2;
    }
    cout << ans << endl;
    return 0;
}