#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <fstream>


using namespace std;

typedef pair<int, int> P;
typedef long long ll;

int N;

int C[11];

int main() {

	cin >> N;

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

	int ans = 0;
	int count = 0;
	for (int i = 1; i <= 10; i++){
		ans += C[i] / 2;
		count += C[i] % 2;
	}

	ans += count / 4;

	cout << ans << endl;

	return 0;
}