#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for (int (i)=(0);(i)<(int)(n);++(i))
using ll = long long;
using P = pair<ll, ll>;
using namespace std;

template<class T> void vin(vector<T>& v, int n) {
    v.resize(n);
    for (int i = 0; i < n; ++i) {
        cin >> v[i];
    }
}

const ll mod = 1e9 + 7;

int main()
{
    ll N, K;
    cin >> N >> K;
    vector<ll> A(N);
    rep(i, N) cin >> A[i];
    sort(A.begin(), A.end());
    ll ans = 1, l = 0, cnt = 0;
    for (int r = N-1; r >= N/2; --r) {
        while (l <= r and A[l] + A[r] <= K) {
            l++; cnt++;
        }
        if (r < l) cnt--;
        ans = (ans * cnt) % mod;
        cnt--;
    }
    cout << ans << endl;
}