#include <iostream>
#include <vector>

using namespace std;

int main(int argc, char* argv[])
{
	int n;
	cin >> n;

	vector<int> itemCount(10);

	for (int i = 0; i < n; ++i) {
		for (int j = 0; j < 3; ++j) {
			int item;
			cin >> item;
			++itemCount[item - 1];
		}
	}

	int powerUpCount = 0;
	int anyItemCount = 0;

	for (int i = 0; i < 10; ++i) {
		while (itemCount[i] >= 2) {
			++powerUpCount;
			itemCount[i] -= 2;
		}
		anyItemCount += itemCount[i];
	}
	powerUpCount += anyItemCount / 4;

	cout << powerUpCount << endl;

	return 0;
}