#include <iostream>
#include <vector>
using namespace std;

int N;
vector<int> a, b, c;

void Solve() {
    int answer = 0, other = 0;
    vector<int> count(10, 0);

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

    for (int i = 0; i < 10; i++) {
        answer += count[i] / 2;
        other += count[i] % 2;
    }

    answer += other / 4;
    cout << answer << endl;
}

int main() {
    cin >> N;

    a = vector<int>(N);
    b = vector<int>(N);
    c = vector<int>(N);

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

    Solve();

    return 0;
}