#if defined(__GNUG__) && !defined(__clang__)
#include <bits/stdc++.h>
#endif

#define inf(T) (numeric_limits<T>::min())
#define sup(T) (numeric_limits<T>::max())
#define rep(i,n) for (int i = 0; i < (n); i++)
#define asc(c) (c).begin(), (c).end()
#define desc(c) (c).rbegin(), (c).rend()
#define mp(...) make_pair(__VA_ARGS__)
#define mt(...) make_tuple(__VA_ARGS__)

using namespace std;

using ll = long long;
using ld = long double;

template <class Key>          using uset = unordered_set<Key>;
template <class Key, class T> using umap = unordered_map<Key, T>;

int main()
{
  cin.tie(0);
  ios::sync_with_stdio(false);

  int n;
  cin >> n;
  vector<int> items(10);
  while (n--) {
    int a, b, c;
    cin >> a >> b >> c;
    items[a - 1] += 1;
    items[b - 1] += 1;
    items[c - 1] += 1;
  }
  int n_up = 0;
  rep(i,10) {
    n_up += items[i] / 2;
    items[i] %= 2;
  }
  n_up += accumulate(asc(items), 0) / 4;
  cout << n_up << endl;

  return 0;
}