#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <stack>
#include <algorithm>
#include <string>
#include <map>
#include <iterator>
#include <set>
#include <queue>

using namespace std;


int main() {

    vector<int> is(10, 0);

    int N;
    cin >> N;
    for (int i = 0; i < N; ++i) {
        int a, b, c;
        cin >> a >> b >> c;
        is[a - 1] += 1;
        is[b - 1] += 1;
        is[c - 1] += 1;
    }

    int cnt = 0;
    int rem = 0;
    for (int i = 0; i < 10; ++i) {
        cnt += is[i] / 2;
        rem += is[i] % 2;
    }
    cnt += rem / 4;

    cout << cnt << endl;

    return 0;
}