#include<iostream>
using namespace std;

int main(void)
{	
	int n, i, j, p=0, sum=0, pa[11] = {0,0,0,0,0,0,0,0,0,0,0}, mo[3];

	cin >> n;

	for (i = 0; i < n; i++) {
		for (j = 0; j < 3; j++) {
			cin >> mo[j];
			pa[mo[j]] += 1;

		}
	}
		for (i = 1; i < 11; i++) {
			sum += pa[i] / 2;
			//cout << sum;
			p += pa[i] % 2;

		}
		sum = sum + p / 4;
	cout << sum;

	return 0;
}