#include <iostream>

using namespace std;

int main (void){
	int N        = 0;
	int a[100]   = { 0 }, b[100] = { 0 }, c[100] = { 0 };
	int item[10] = { 0 };
	int level    = 0;

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

	// solve
	for(int i = 0; i < N; i++){
		item[a[i] - 1]++;
		item[b[i] - 1]++;
		item[c[i] - 1]++;
	}

	for(int i = 0; i < 10; i++){
		level  += item[i] / 2;
		item[i] = item[i] % 2;
	}

	int sum = 0;
	for(int i = 0; i < 10; i++){
		sum += item[i];
	}
	level += sum / 4;

	// output
	cout << level << endl;

	return 0;
}