#include <stdio.h>
#include <algorithm>
#include <deque>
using namespace std;
using ll = long long;

//29
int main() {
	int n, a, b, c, count[10] = { 0 };
	scanf("%d", &n);
	for (int i = 0; i < n; i++) {
		scanf("%d %d %d", &a, &b, &c);
		count[a - 1]++, count[b - 1]++, count[c - 1]++;
	}
	int total = 0, rem = 0;
	for (int i = 0; i < 10; i++) {
		total += count[i] / 2;
		rem += count[i] & 1;
	}
	total += rem / 4;
	printf("%d\n", total);
}