#include <bits/stdc++.h>
using namespace std;
#define MOD 999917

int vf[2000000];
int a[1012];
long long int sume[1012];
unordered_map<int,int> mp;
int main(void){
    ofstream cout("oite.out");
    ifstream cin("oite.in");
    int n, L;
    cin >> n >> L;
   /// cout << L << endl;
    for(int i = 1;i<=n;i++){
        cin >> a[i];
    }
    int ans =0 ;
    for(int i = 1;i<=n;i++){
        for(int j = i+1;j<=n;j++){
            int suma = L - (a[i] + a[j]);
            if(mp.count(suma)){
                ans += mp[suma];
            }
        }
        for(int j = i-1;j>=1;j--){
            mp[a[i] + a[j]]++;
        }
    }
    cout << ans;

}