#include <bits/stdc++.h>

#define FOR(i, a, b) for (ll i = (a); i < (b); i++)
#define RFOR(i, a, b) for (ll i = (b)-1; i >= (a); i--)
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define rep1(i, n) for (ll i = 1; i <= (n); i++)
#define rrep(i, n) for (ll i = (n)-1; i >= 0; i--)

#define pb push_back
#define mp make_pair
#define fst first
#define snd second
#define show(x) cout << #x << " = " << x << endl
#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)
#define pii pair<int, int>
#define vi vector<int>

using namespace std;
template <class S, class T>
ostream& operator<<(ostream& o, const pair<S, T>& p)
{
    return o << "(" << p.first << "," << p.second << ")";
}
template <class T>
ostream& operator<<(ostream& o, const vector<T>& vc)
{
    o << "sz = " << vc.size() << endl
      << "[";
    for (const T& v : vc)
        o << v << ",";
    o << "]";
    return o;
}
using ll = long long;
constexpr ll MOD = 1000000007;


int main()
{
    int N;
    cin >> N;
    int item[10] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
    rep(i, N)
    {
        int a, b, c;
        cin >> a >> b >> c;
        a--, b--, c--;
        item[a]++;
        item[b]++;
        item[c]++;
    }
    int num = 0;
    for (int i = 0; i < 10; i++) {
        num += item[i] / 2;
    }
    const int rest = 3 * N - num * 2;
    num += rest / 4;
    cout << num << endl;

    return 0;
}