#include <fstream>
#include <algorithm>
#include <unordered_map>

using namespace std;

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

const int NMAX = 1024;

unordered_map<long long, int> lhs;

long long v[NMAX + 1];

int main() {
	long long L;
	int n;
	fin>>n>>L;
	for( int i = 1; i <= n; i ++ ) {
		fin>>v[i];
	}

	long long ans = 0;
	//sort(v+1, v+n+1);
	for( int i = 1; i <= n; i ++ ) {
		for( int j = i + 1; j <= n; j ++ ) 
			ans += lhs[L - v[i] - v[j]];
		
		for( int j = 1; j < i; j ++ ) 
			lhs[v[j] + v[i]] ++;
	}

	fout<<ans;
}