#include <bits/stdc++.h>

typedef long long ll;
#define rep(i, b) for(int i = 0; i < b; i++)
#define repi(i, a, b) for(int i = a; i < b; i++)
#if defined(_MSC_VER) || __cplusplus > 199711L
#define aut(r,v) auto r = (v)
#else
#define aut(r,v) __typeof(v) r = (v)
#endif
#define each(it,o) for(aut(it, (o).begin()); it != (o).end(); ++ it)
#define MAX_V 1001
#define MAX_E 401
#define MOD 1000000007
#define EPS 1e-5
#define INF INT_MAX
#define PI 3.141
inline ll toll(std::string s) { ll v; std::istringstream sin(s); sin >> v; return v; }
template<class T> inline std::string toString(T x) { std::ostringstream sout; sout << x; return sout.str(); }
using namespace std;
typedef pair<int, int> pii;

int item[10];

int main()
{
	int N;
	int res = 0;
	cin >> N;
	rep(i, N)
	{
		int a;
		rep(i, 3)
		{
			cin >> a;
			item[a - 1]++;
		}
	}

	rep(i, 10)
	{
		res += item[i] / 2;
		item[i] = item[i] % 2;
	}

	int one = 0;
	rep(i, 10)
	{
		one += item[i];
	}
	res += one / 4;

	cout << res << endl;
	return 0;
}