#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
ll const mod = 1e9+7;

#define p_ary(ary,a,b,i) do { cout << "["; for (int (i) = (a);(i) < (b);++(i)) cout << ary[(i)] << ((b)-1 == (i) ? "" : ", "); cout << "]\n"; } while(0)
#define p_map(map,it) do {cout << "{";for (auto (it) = map.begin();;++(it)) {if ((it) == map.end()) {cout << "}\n";break;}else cout << "" << (it)->first << "=>" << (it)->second << ", ";}}while(0)

const int MAX_N = 100010;
ll fact[MAX_N],fact_inv[MAX_N],inv[MAX_N];

ll pow_mod(ll a,ll b) {
    ll ret;
    if (b < 0) ret = pow_mod(a,mod+b-1);
    else if (b == 0) ret = 1;
    else if (b == 1) ret = a;
    else {
        ll c = pow_mod(a,b/2);
        if (b%2) ret = (c*c)%mod*a%mod;
        else ret = c*c%mod;
    }
    return ret;
}

void create_table(int n) {
    fact[0] = 1;fact[1] = 1;
    for (int i = 2;i <= n;++i) fact[i] = fact[i-1]*i%mod;
    fact_inv[n] = pow_mod(fact[n],mod-2);
    for (int i = n;i > 0;--i) fact_inv[i-1] = fact_inv[i]*i%mod;
    for (int i = 1;i <= n;++i) inv[i] = fact_inv[i]*fact[i-1]%mod;
}

int main() {
    int n,k;
    ll ans = 1;
    cin >> n >> k;
    vector<int> a(n),b(n,0);
    for (int i = 0;i < n;++i) cin >> a[i];
    sort(a.begin(),a.end());
    bool ok = true;
    for (int i = 0;i < n/2;++i) if (a[i]+a[n-i-1] > k) ok = false;
    if (!ok) ans = 0;
    int j = n-1;
    for (int i = 0;i < n;++i) {
        while (j >= 0 && a[i]+a[j] > k) j--;
        b[i] = max(n/2,j+1);
    }
    for (int i = 0;i < n-1;++i) if (a[i]+a[i+1] < k) j = (2*i+4-n)/2;
    for (int i = 0;i < n;++i) {
        ans *= b[n-1-i]-i;
        ans %= mod;
    }
    create_table(n);
    ans *= fact_inv[n/2];
    ans %= mod;
    ans *= pow_mod(2,-j);
    ans %= mod;
    cout << ans << endl;
    return 0;
}