#define REP(i, n) for(int i = 0;i < n;i++)
#define REPR(i, n) for(int i = n;i >= 0;i--)
#define FOR(i, m, n) for(int i = m;i < n;i++)

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;
int main() {
	int ans,n;
	cin >> n;

	int item[10] = {0};
	int tmp;
	REP(i,n){
		REP(j,3){
			cin >> tmp;
			item[tmp-1] += 1;
		}
	}
	int answer = 0;
	tmp = 0;
	REP(i,10){
		answer += item[i]/2;
		tmp += item[i]%2;
	}
	cout << answer+tmp/4 << endl;
	return 0;
}