#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
ll mod=1000000007;
int main(){
    ll n,k;cin>>n>>k;
    vector<ll> a(n);for(ll i=0;i<n;i++)cin>>a[i];
    sort(a.begin(),a.end());
    ll are[n+2];
    are[0]=0;
    are[1]=1;
    for(ll i=2;i<=n+1;i++){
        ll u=are[i-1]*(2*i-1);
        u%=mod;
        are[i]=u;
    }
    ll tai[n];
    for(ll i=n-1;i>=0;i--){
        ll y=k-a[i];
        ll u=upper_bound(a.begin(),a.end(),y)-a.begin();
        tai[i]=u;
    }
    for(ll i=0;i<n/2;i++){
        if(a[i]+a[n-1-i]>k){
            cout<<0<<endl;
            return 0;
        }
    }
    ll ans=0;
    ll now=1;
    for(ll i=n-1;i>=0;i--){
        ll sum=1;
        ll t=tai[i];
        if(t>=i)break;
        if(i<n-1){
            now*=(t-n+2+i);
            now%=mod;
        }
        sum*=now*(i-t);
        sum%=mod;
        sum*=are[n/2-n+i];
        sum%=mod;
        ans+=sum;
        ans%=mod;
            
    }
    ll rr=are[n/2];
    ll anss=rr-ans;
    anss+=mod;
    cout<<anss%mod<<endl;
    
}