#include <bits/stdc++.h>
#define REP(i,n) for(int i=0; i<(n); i++)
using namespace std;
struct cww{cww(){ios::sync_with_stdio(false);cin.tie(0);}}star;
int main()
{
	int N;
	cin >> N;
	vector<int> vc( N*3 );
	for( auto& x : vc )
	{
		cin >> x;
	}
	sort( vc.begin(), vc.end() );
	int count{}, tmp{};
	REP( i, N*3 )
	{
		if( vc[i] == vc[i+1] )
		{
			count++;
			i += 1;
		}
		else
		{
			tmp++;
			if( tmp == 4 )
			{
				count++;
				tmp = 0;
			}
		}
	}
	cout << count << endl;
	return 0;
}