// Contoh Bab 11: brute force semua pasangan.
//
// Compile:  g++ -std=c++17 -O2 -o pasangan exercises/11/01-semua-pasangan.cpp
// Jalankan: ./pasangan
// Contoh masukan: 5 10
//                 3 7 2 8 5

#include <iostream>
using namespace std;

const int MAKS = 5005;
int a[MAKS];

int main() {
    int n, k;
    cin >> n >> k;
    for (int i = 0; i < n; i++) cin >> a[i];

    int banyak = 0;
    for (int i = 0; i < n; i++)
        for (int j = i + 1; j < n; j++)
            if (a[i] + a[j] == k) banyak++;

    cout << banyak << "\n";
    return 0;
}