#include <iostream>
#include <string>
#include <utility>
#include <algorithm>
#include <map>
#include <set>
#include <vector>
#include <cmath>
#include <cstdlib>
#include <queue>
#include <stack>
#include <iomanip>

using namespace std;

#define REP(i, n) for(ll i = 0;i < n;i++)
#define REPR(i, n) for(ll i = n;i >= 0;i--)
#define FOR(i, m, n) for(ll i = m;i < n;i++)
#define FORR(i, m, n) for(ll i = m;i >= n;i--)
#define REPO(i, n) for(ll i = 1;i <= n;i++)
#define ll long long
#define INF (ll)1 << 60
#define MINF (-1 * INF)
#define ALL(n) n.begin(),n.end()
#define MOD 1000000007
#define P pair<ll, ll>

ll n, a = 0, b = 0, s[11];
int main() {
	cin >> n;
	REP(i, n * 3) {
		ll a; cin >> a;
		s[a - 1]++;
	}
	REP(i, 10) {
		a += s[i] / 2;
		b += s[i] % 2;
	}
	cout << a + b / 4 << endl;
}