#include <iostream>
#include <vector>
#include <numeric>
using namespace std;

int main() {
    int N;
    cin >> N;
    vector<int> v(11);
    for(int i=0; i<N; ++i) {
        int a, b, c;
        cin >> a >> b >> c;
        v[a]++; v[b]++; v[c]++;
    }
    int res = 0;
    for(int i=0; i<v.size(); ++i) {
        res += v[i] / 2;
        v[i] %= 2;
    }
    cout << res + accumulate(v.begin(), v.end(), 0)/4 << endl;
}