#include<iostream>
#include<algorithm>
#include <vector>
#include<cmath>
#include<iomanip>
using namespace std;
typedef long long int lont;
int main() {
	int N;
	cin >> N;

	int M = N * 3;
	int cnta = 1;
	int suma = 0;

	vector<int>veca(M+1);
	for (int ia = 0; ia < M; ia++) {
		cin >> veca.at(ia);
	}

	sort(veca.begin(), veca.end());
	reverse(veca.begin(), veca.end());

	for (int ib = 0; ib < M; ib++) {
		if (veca.at(ib) == veca.at(ib + 1)) {
			cnta++;
		}
		else {
			suma += cnta / 2;
			cnta = 1;
		}
	}
	cout << suma + (M - suma * 2) / 4 << endl;
}