#include <iostream>
#include <algorithm>
#include <cstring>
#include <climits>
using namespace std;

int main()
{
	int N, a, b, c, ans = 0, item[11] = { 0 };
	cin >> N;

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

	int temp = 0;
	for (int i = 1; i <= 10; ++i)
	{
		ans += item[i]/2;
		temp += item[i] & 1;
	}
	ans += temp / 4;

	cout << ans << endl;

	return 0;
}