#include <iostream>
#include <unordered_map>
#include <fstream>
using namespace std;
uint32_t C, L;

int v [1030];

int main()
{
    int sol = 0;
    unordered_map <int, int> H;
    ifstream in ("oite.in");
    ofstream out ("oite.out");
    in>>C>>L;

    for(int i = 0; i < C; ++i)
        in>>v[i];

    for(int i = 2; i < C; ++i)
    {
        for(int j = i - 2; j >= 0; --j)
            H[v[i-1] + v[j]] ++;
        for(int j = i + 1; j < C; ++j)
            if(H[L - v[i] - v[j]] != 0)
                sol += H[L-v[i] - v[j]];
    }

    out<<sol;
}