#include<iostream>
#include<cstdio>
#include<string>
#include<vector>
#include<queue>
#include<set>
#include<sstream>
#include<algorithm>
using namespace std;

#define ALL(x) (x).begin(),(x).end()
#define RALL(x) (x).rbegin(), (x).rend()
#define rep(i,n) for(int i=0;i<n;i++)
#define rev(j,m) for(int j=1;j<m;j++)

typedef vector<pair<int,int> > pii;


int main(){
	int n,x,A[10]={0},sum=0,ans=0;
	cin >> n;
	rep(i,n){
		rep(j,3){
			cin >> x;
			A[x-1]++;
		}
	}
	
	rep(i,10){
		ans+=A[i]/2;
		A[i]%=2;
		sum+=A[i];
	}
	cout << ans+sum/4 << endl;
	return 0;
}