#define _USE_MATH_DEFINES
#include  <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <string>
#include<math.h>
#include<iomanip>
#include<stdio.h>
#include <stdlib.h>
#include<stdio.h>
#include <queue>
#include<map>
#include <fstream>
#include <sstream>
#include<set>
#include<stack>
#include<time.h>
#include <sys/types.h>
#include <tuple>
#include <numeric>
#include <iterator>

typedef long long int ll;
//#include<bits/stdc++.h>


using namespace std;





int main()
{

    int Q;
    Q = 1;
    //cin >> Q;


    while (Q--) {
        int n;
        cin >> n;
        int x = 0;
        int d[20] = {};
        for (int i = 0; i < n; i++) {
            int a, b, c;
            cin >> a >> b >> c;
            d[a]++; d[b]++; d[c]++;
            x += d[a] / 2; d[a] %= 2;
            x += d[b] / 2; d[b] %= 2;
            x += d[c] / 2; d[c] %= 2;
        }
        int t = 0;
        for (int i = 0; i <= 10; i++) {
            t += d[i];
        }
        x += t / 4;
        cout << x;
    }
    return 0;
}