#include "bits/stdc++.h"
using namespace std;
using Graph = vector<vector<int>>;
typedef long long ll;
typedef pair<ll, ll> P;
#define rep(i,n) for (ll i = 0; i < (n); ++i)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
const long long mod = 1e9 + 7;

ll gcd(ll a, ll b) {
	return b ? gcd(b, a % b) : a;
}

ll lcm(ll a, ll b) {
	return a / gcd(a, b) * b;
}

int main() {
	ll n;
	cin >> n;
	
	map<ll, ll> m;

	rep(i, n) {
		ll a, b, c;
		cin >> a >> b >> c;
		m[a]++;
		m[b]++;
		m[c]++;
	}

	ll ans = 0;

	for (auto p : m) {
		if (p.second >= 2) {
			ans+= p.second/2;
			m[p.first] %= 2;
		}
	}

	ll cnt=0;

	for (auto p : m) {
		if (p.second != 0) {
			cnt++;
		}
		if (cnt == 4) {
			ans++;
			cnt = 0;
		}
	}

	cout << ans << endl;
}