#include <iostream>
#include <unordered_map>

#define MAXN 1028

using namespace std;

int C, L, oite[MAXN];
unordered_map<int, int> sume; // sume[i] = frecventa sumei i


int main()
{
    freopen("oite.in", "r", stdin);
    freopen("oite.out", "w", stdout);
    scanf("%d %d", &C, &L);

    for(int i = 1; i <= C; i++) {
        scanf("%d", &oite[i]);
    }

    int ans = 0;
    for(int i = 1; i < C; i++) {
        for(int j = i + 1; j <= C; j++) {
            ans += sume[L - oite[i] - oite[j]];
        }
        for(int j = 1; j < i; j++) {
            sume[oite[i] + oite[j]]++;
        }
    }

    printf("%d", ans);

    return 0;
}