#include <bits/stdc++.h>
#define FOR(i,a,b) for(int i = (a); i < (b); ++i)
using namespace std;

int main() {
	int n;
	cin >> n;
	int item[16] = { 0 };
	FOR(i, 0, n) {
		int a, b, c;
		cin >> a >> b >> c;
		item[a]++; item[b]++; item[c]++;
	}
	int cnt = 0, sum = 0;
	FOR(i, 1, 11) {
		cnt += item[i] / 2;
		sum += item[i] % 2;
	}
	cout << cnt + sum / 4 << endl;
	return 0;
}