#include <iostream>
#include <vector>
#include <cmath>
#include <algorithm>
#include <string>
#include <map>
using namespace std;


int main(){
    int N;
    cin >> N;
    vector<int> m(11, 0);
    int a1,a2,a3;
    for(int i=0; i<N; i++){
        cin >> a1 >> a2 >> a3;
        m[a1] = m[a1] + 1;
        m[a2] = m[a2] + 1;
        m[a3] = m[a3] + 1;
    }

    int res = 0;
    for(int i=1; i<m.size(); i++){
        if(m[i] >= 2){
            res += m[i]/2;
            m[i] = m[i]%2;
        }
    }

    res += (count(m.begin(), m.end(), 1))/4;
    cout << res << endl;
}