#include <bits/stdc++.h>

using namespace std;

int main() {
	int N; cin >> N;
	vector<int> item(100, 0);
	for (int i = 0; i < N; ++i) {
		for (int j = 0; j < 3; ++j) {
			int id; cin >> id; --id;
			item[id]++;
		}
	}
	int ans = 0, rest = 0;
	for (int i = 0; i < item.size(); ++i) {
		ans += item[i]/2;
		rest += item[i]%2;
	}
	ans += rest/4;
	cout << ans << endl;
}