#include <iostream>
#include <math.h>
#include <algorithm>
#include <functional>
#include <vector>
#include <typeinfo>
#include <climits>
#include <ctype.h>
#include <string>
using namespace std;
#define INIT cin.tie(0); ios::sync_with_stdio(false);
#define FOR(i, a, n) for (int i = a; i < n; i++)
#define REP(i, n) for(int i = 0; i < n; i++)

int main()
{
    INIT;

    int n;
    cin >> n;

    int A[10] = {};
    REP(i, n){
        int a, b, c;
        cin >> a >> b >> c;
        A[a - 1]++;
        A[b - 1]++;
        A[c - 1]++;
    }

    int cnt = 0;
    int c = 0;
    REP(i, 10){
        if(A[i] >= 2) cnt += A[i] / 2;
        if(A[i] == 1) c++;
        if(c == 4){
            cnt++;
            c = 0;
        }
    }
    cout << cnt << endl;


    return 0;
}