#define _USE_MATH_DEFINES
#include<stdio.h>
#include<string>
#include<iostream>
#include<cctype>
#include<cstdio>
#include<vector>
#include<stack>
#include <algorithm>
#include<math.h>
#include<set>
#include<map>
#include<iomanip>
//#include<bits/stdc++.h>


using namespace std;

int main(){

int n;
cin>>n;
int t=3*n;
int y[20]={};
for(int i=0;i<n;i++){
	int a,b,c;
	cin>>a>>b>>c;
	y[a]++;y[b]++;y[c]++;
}
int x=0;
for(int i=0;i<=9;i++){
	x+=y[i]/2;
	t-=y[i]-y[i]%2;
}

x+=t/4;
cout<<x<<endl;
	return 0;
}