#include <bits/stdc++.h>
using namespace std;

int main() {
	int N;
	cin >> N;

	vector<int> v(100, 0);
	for (int i = 0; i < N; i++) {
		int a, b, c;
		cin >> a >> b >> c;

		v.at(a - 1)++;
		v.at(b - 1)++;
		v.at(c - 1)++;
	}

	sort(v.begin(), v.end());
	reverse(v.begin(), v.end());
	int sum = 0;
	for (int i = 0; i < v.size(); i++) {
		int& p = v.at(i);
		if (p < 2) break;

		sum += p / 2;
		p %= 2;
	}
	int c = 0;
	for (int i = 0; i < v.size(); i++) {
		if (v.at(i) == 1) {
			c++;
		}

		if (i == v.size() - 1) {
			sum += c / 4;
		}
	}

	cout << sum << endl;
}