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

int main(void) {
	cin.tie(0);
	ios::sync_with_stdio(false);
	
	int n, a, b, c;
	cin >> n;
	vector<int> items(11, 0);
	for (int i = 0; i < n; ++i) {
		cin >> a >> b >> c;
		++items[a]; ++items[b]; ++items[c];
	}
	int ans = 0;
	for (int i = 0; i < 11; ++i) {
		if (items[i] >= 2) {
			ans += items[i] / 2;
			items[i] = items[i] % 2;
		}
	}
	int sum = accumulate(items.begin(), items.end(), 0);
	ans += sum / 4;
	cout << ans;
	return 0;
}