#include <bits/stdc++.h>
using namespace std;
typedef long long i64;

const int SPQR = 1050,  ///Ave Imperator, morituri te salutant!
           MOD = 33037;


int v[SPQR];

unordered_map<int, int> mp;

int main(void) {
    ifstream fi("oite.in");
    ofstream fo("oite.out");
    int n, ant;
    i64 l;

    ant = 0;

    fi >> n >> l;
    for(int i=1; i<=n; ++i)
        fi >> v[i];

    for(int i=1; i<=n; ++i) {
        for(int j=i+1; j<=n; ++j)
            ant += mp[l-v[i]-v[j]];
        for(int j=i-1; j>=1; --j)
            ++ mp[v[i]+v[j]];
    }

    fo << ant << '\n';

    return 0;
}