#include <bits/stdc++.h>
using namespace std;
bool isPrime(long long n) {
  if (n <= 1) return false;
  if (n <= 3) return true;
  if (n % 2 == 0 || n % 3 == 0) return false;
  for (long long i = 5; i * i <= n; i = i + 6)
    if (n % i == 0 || n % (i + 2) == 0) return false;
  return true;
}
int main() {
  int n, k, c = 0;
  cin >> n >> k;
  vector<int> v;
  int a;
  for (int i = 0; i < n; i++) {
    cin >> a;
    v.push_back(a);
  }
  sort(v.begin(), v.end());
  for (int i = 0; i < n; i++) {
    if (v[i] + k <= 5) c++;
  }
  cout << c / 3;
  return 0;
}
