#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <climits>
#include <cassert>
#include <iostream>
#include <iomanip>
#include <string>
#include <stack>
#include <queue>
#include <vector>
#include <map>
#include <set>
#include <algorithm>
#include <numeric>
#include <bitset>

#define all(c) c.begin(), c.end()
#define rall(c) c.rbegin(), c.rend()
#define debug(x) cerr << #x << ": " << x << endl

using namespace std;

typedef long long ll;
typedef pair<ll, ll> Pll;
typedef pair<int, int> Pii;

const ll MOD = 1000000007;
const long double EPS = 1e-10;
const int dyx[4][2] = {
    { 0, 1}, {-1, 0}, {0,-1}, {1, 0}
};

int main() {
    int n;
    ll k;
    cin >> n >> k;
    vector<ll> a(n);
    for(int i=0;i<n;++i) {
        cin >> a[i];
    }
    sort(all(a));


    vector<ll> b(n);
    for(int i=0;i<n;++i) {
        b[i] = distance(a.begin(), upper_bound(a.begin(), a.begin()+i, k-a[i]));
    }

    ll ans = 1LL;
    for(int i=n-1;i>n-1-n/2;--i) {
        ans *= b[i] - (n-1-i);
        ans %= MOD;
    }
    cout << ans << endl;
}