#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for(int i = 0; i < (n); i++)
#define rep1(i, n) for(int i = 1; i <= (n); i++)
#define co(x) cout << (x) << "\n"
#define cosp(x) cout << (x) << " "
#define ce(x) cerr << (x) << "\n"
#define cesp(x) cerr << (x) << " "
#define pb push_back
#define mp make_pair
#define Would
#define you
#define please


int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);


	int N;
	cin >> N;
	int A[11] = {};

	rep(i, 3 * N) {
		int P;
		cin >> P;
		A[P]++;
	}
	int kotae = 0;
	rep1(i, 10) {
		kotae += A[i] / 2;
	}
	kotae += (3 * N - kotae * 2) / 4;
	co(kotae);

	Would you please return 0;
}