#include <bits/stdc++.h>

using namespace std;

const int NMAX = 1024;

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

map <int, int> mp;
map <int, int> ss;

int C, L, v[NMAX+1];
int ans;

int main()
{
    fin >> C >> L;
    for(int i=1; i<=C; i++)
        fin >> v[i], ss[v[i]]++;
    int cnt = 0;
    for( pair<int,int> p : ss)
    {
        int cate = p.second;
        while(cate)
            v[++cnt] = p.first, cate--;
    }
    for(int i=1; i<=C; i++)
    {
        for(int j=i+1; j<=C; j++)
            ans+=mp[L-v[i]-v[j]];
        for(int j=1; j<i; j++)
            mp[v[i]+v[j]]++;
    }
    fout << ans;
}