#include<bits/stdc++.h>

using namespace std;
ifstream fin("oite.in");
ofstream fout("oite.out");
unordered_map<int,int> m;
int n,l,a[1009],i,j,ans;
int main(){
	fin>>n>>l;
for(i=1;i<=n;i++)
{
	fin>>a[i];
}
sort(a+1,a+1+n);
for (int i = 3; i <= n; i++) {
        for (int j = 1; j < i-1; j++)
            m[a[j] + a[i-1]]++;
        for (int j = i+1; j <= n; j++)
            ans += m[l-a[i]-a[j]];
    }

fout<<ans;
return 0;
}