module main;

import std;

void main()
{
	auto N = readln.chomp.to!int;
	auto items = new int[](11);
	int ans = 0;
	foreach (_; 0 .. N) {
		int a, b, c;
		readln.chomp.formattedRead("%d %d %d", a, b, c);
		items[a]++, items[b]++, items[c]++;
		if (items[a] >= 2) {
			items[a] -= 2;
			ans++;
		}
		if (items[b] >= 2) {
			items[b] -= 2;
			ans++;
		}
		if (items[c] >= 2) {
			items[c] -= 2;
			ans++;
		}
	}
	writeln(ans + items.count(1) / 4);
}