#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int (i) = 0 ; (i) < (int)(n) ; (i)++)
#define REP(i,a,b) for(int (i) = a ; (int)(i) <= (int)(b) ; (i)++)
#define all(n) (n).begin(),(n).end()
typedef vector<int> Vi;
typedef vector<Vi> VVi;
typedef pair<int,int> Pii;
typedef vector<Pii> VPii;


int main(){
	int N;
	cin >> N;
	int C[11] = {};
	rep(i,N){
		int a,b,c;
		cin >> a >> b >> c;
		C[a]++;
		C[b]++;
		C[c]++;
	}
	int ans = 0;
	int sub = 0;
	REP(i,1,10){
		ans += C[i] / 2;
		sub += C[i] % 2;
	}
	cout << ans + sub / 4 << endl;
}