#include <iostream>
#include <iomanip>

#include <algorithm>
#include <string>
/////////
#define REP(i, x, n) for(int i = x; i < n; i++)
#define rep(i,n) REP(i,0,n)
#define P(p) cout<<(p)<<endl;
/////////
typedef long long LL;
typedef long double LD;
/////////
using namespace::std;
/////////

int main(void){
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout << fixed;//
	//cout << setprecision(7);//
	
	int N;
	cin >> N;
	int item[11];
	rep(i,11)item[i]=0;

	int a,b,c;
	rep(i,N){
		cin >>a>>b>>c;
		item[a]++;
		item[b]++;
		item[c]++;
	}
	////////////
	int ans = 0;
	rep(i,11){
		ans += item[i]/2;
		item[i] = item[i]%2;
	}
	int sum=0;
	rep(i,11){
		if(item[i]>0)++sum;
	}
	ans += sum/4;

	P(ans);
	return 0;
}