#include "bits/stdc++.h"

using namespace std;
using ll = long long;
const double pi = acos(-1);
#define FOR(i,a,b) for (ll i=(a),__last_##i=(b);i<__last_##i;i++)
#define RFOR(i,a,b) for (ll i=(b)-1,__last_##i=(a);i>=__last_##i;i--)
#define REP(i,n) FOR(i,0,n)
#define RREP(i,n) RFOR(i,0,n)
#define __GET_MACRO3(_1, _2, _3, NAME, ...) NAME
#define rep(...) __GET_MACRO3(__VA_ARGS__, FOR, REP)(__VA_ARGS__)
#define rrep(...) __GET_MACRO3(__VA_ARGS__, RFOR, RREP)(__VA_ARGS__)
template<typename T> ostream& operator<<(ostream& os, const vector<T>& v) {
	REP(i, v.size()) { if (i)os << " "; os << v[i]; }return os;
}
template<typename T> ostream& operator<<(ostream& os, const vector<vector<T>>& v) {
	REP(i, v.size()) { if (i)os << endl; os << v[i]; }return os;
}

int main() {
	ll n, a, b, c;
	ll sum = 0;
	ll ans = 0;
	vector<ll> v(10, 0);
	
	cin >> n;

	REP(i, n) {
		cin >> a >> b >> c;
		v[a - 1]++;
		v[b - 1]++;
		v[c - 1]++;
	}

	REP(i, 10) {
		ans += v[i] / 2;
		v[i] = v[i] % 2;
		sum += v[i];
	}

	ans += sum / 4;

	cout << ans << endl;
}