#include<iostream>
#include<string>
#include<cstring>
#include<complex>
#include<vector>
#include<algorithm>
#include<cstdlib>
#include<cmath>
#include<iomanip>
#include<numeric>
using namespace std;

#define REP(i, j) for (int i = 0; i < (int)j; ++i)
#define FOR(i, j, k) for (int i = (int)j; i < (int)k; ++i)
#define SORT(v) sort(v.begin(), v.end())
#define REVERSE(v) reverse(v.begin(), v.end())
typedef complex<double> P;
typedef vector<int> VI;
typedef long long LL;
typedef pair<int,int> PII;

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

	int n;
	cin >> n;

	VI items(11,0);
	REP(i,n) {
		int a, b, c;
		cin >> a >> b >> c;
		items[a]++;
		items[b]++;
		items[c]++;
	}

	int pu = 0;
	FOR(i,1,11) {
		pu += items[i] / 2;
		items[i] %= 2;
	}
	pu += accumulate(items.begin(), items.end(), 0) / 4;

	cout << pu << endl;

	return 0;
}