#include<iostream>
#include<stdio.h>
#include<vector>
#include<algorithm>

using namespace std;

int main(){
    int n;
    cin>> n;
    vector<int> vec(10);

    int a, b, c;
    for(int i=0; i<n; i++){
        cin>> a>> b>> c;
        vec[a-1]++;
        vec[b-1]++;
        vec[c-1]++;
    }

    int ans = 0, amari = 0;
    for(int i=0; i<10; i++){
        ans += vec[i]/2;
        amari += vec[i]%2;
    }
    amari = amari/4;

    cout<< ans+amari<< endl;


    return 0;
}