#include <bits/stdc++.h>
using namespace std;

int main() {
	int n;
	int z[10] = { 0 };

	cin >> n;

	for (int i = 0; i < n; i++) {
		int a, b, c;
		cin>>a>>b>>c;
		z[a - 1]++;
		z[b - 1]++;
		z[c - 1]++;
	}
	int tsum = 0;
	int fsum = 0;
	for (int j = 0; j < 10; j++) {
		tsum += z[j] / 2;
		fsum += z[j] % 2;
	}
	cout << tsum + fsum / 4 << endl;

}