#include<bits/stdc++.h>
#pragma GCC optimize("03")
using namespace std;
typedef long long ll;
#define all(a) (a).begin(), (a).end()
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define rc(s) return cout<<s,0
#define pi pair <int, int>
#define sz(x) (int)((x).size())
//#define int long long

const int N = 2e3 + 11;

ifstream in ("oite.in");
ofstream out ("oite.out");

int a[N], L, n;
unordered_map<int,int>m;

void solve(){

    in >> n >> L;

    for(int i = 1; i <= n; i++)in >> a[i];

    sort(a + 1, a + n + 1);

    ll ans = 0;

    for(int i = 3; i < n; i++){

        //pairs till now
        for(int j = 1; j < i - 1; j++){
            m[a[i - 1] + a[j]]++;
        }

        //pairs with a[i]
        for(int j = i + 1; j <= n; j++){
            int sum = L - a[i] - a[j];
            if(sum >= 0)ans += m[sum];
        }
    }

    out << ans << '\n';

}

int main(){
ios_base :: sync_with_stdio(0); cin.tie(); cout.tie();

    int t = 1;

    //cin >> t;

    while(t--){

        solve();

    }

}