#include <iostream>		//cin, cout
#include <vector>		//vector
#include <algorithm>	//sort,min,max,count
#include <string>		//string,getline, to_string
#include <cstdlib>		//abs(int)
#include <utility>		//swap, pair
#include <deque>		//deque
#include <climits>		//INT_MAX
#include <bitset>		//bitset


using namespace std;

int main() {

	int N;
	cin >> N;

	int a, b, c;
	vector<int> p(11);

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

	int ans = 0;
	int oth = 0;

	for (int i = 1; i <= 10; i++) {
		ans += p[i] / 2;
		oth += p[i] % 2;
	}

	ans += oth / 4;

	cout << ans << endl;

	return 0;

}