#include<iostream>
#include<string>
#include<fstream>
#include<iomanip>
#include<vector>
#include<cctype>
#include<algorithm>
using namespace std;
static const int MAX_N = 1000005;

int main()
{
	int n, a, b, c, t[11] = {};
	cin >> n;
	for (int i = 0; i < n; i++)
	{
		cin >> a >> b >> c;
		t[a]++;
		t[b]++;
		t[c]++;
	}
	int sum = 0, sum1 = 0;
	for (int i = 1; i <= 10; i++)
	{
		sum += t[i] / 2;
		t[i] %= 2;
		sum1 += t[i];
	}
	sum += sum1 / 4;
	cout << sum << endl;
	return 0;
}