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

int main()
{
	int n, i, item[10] = {}, a, b, c, ans = 0;
	cin >> n;
	for (i = 0; i < n; ++i) {
		cin >> a >> b >> c;
		item[a - 1]++;
		item[b - 1]++;
		item[c - 1]++;
	}
	for (i = 0; i < 10; ++i) {
		ans += item[i] / 2;
		item[i] %= 2;
	}
	ans += accumulate(item, item + 10, 0) / 4;
	cout << ans << endl;
	return 0;
}