#include <iostream>	//cin, cout
#include <vector>	//vector
#include <algorithm> //sort,min,max
#include <string>	//string
#include <ios>		//fixed
#include <iomanip>	//setprecision
#include <utility> //swap

using namespace std;

int main() {

	int N;
	cin >> N;

	vector<int> A(11);

	int temp;
	for (int i = 0; i < N; i++) {
		for (int j = 0; j < 3; j++) {
			cin >> temp;
			A[temp]++;
		}
	}
	
	int ans = 0;
	temp = 0;
	for (int i = 1; i < 11; i++) {
		ans += A[i] / 2;
		temp += A[i] % 2;
	}

	ans += temp / 4;
	cout << ans << endl;

	return 0;

}