#include <vector>
#include <string>
#include <algorithm>
#include <numeric>
#include <iostream>
#include <cstdlib>
#include <cstring>
#include <utility>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <iterator>
#include <cmath>
#include <iomanip>
using namespace std;

using ull = unsigned long long;
using ll = long long;

int main()
{
    int n;
    cin >> n;
    int item[10] = {};

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

    int sum = 0;
    for(int i = 0; i < 10; ++i)
    {
        sum += item[i]/2;
        item[i]%= 2;
    }

    sum += accumulate(begin(item),end(item),0) /4;

    cout << sum << endl;
}