#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define repp(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define all(v) v.begin(), v.end()
using namespace std;
using ll = long long int;

int main() {
    // 入力
    int N;
    cin >> N;
    vector<int> item(11);
    rep(i, N) {
        int a, b, c;
        cin >> a >> b >> c;
        item[a]++;
        item[b]++;
        item[c]++;
    }

    // パワーアップ回数
    int remain = 0, powerup = 0;
    repp(i, 1, 11) {
        while (item[i] >= 2) {
            item[i] -= 2;
            powerup++;
        }
        remain += item[i];
    }
    powerup += remain / 4;

    // 出力
    cout << powerup << endl;
}