#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <math.h>
using namespace std;

int main() {
    int n,ans = 0,leave = 0;
    cin >> n;
    vector<int> item(11,0);
    for(int i = 0;i < n;i++){
        int a,b,c;
        cin >> a >> b >> c;
        item[a]++;
        item[b]++;
        item[c]++;
    }
    for(int i = 1;i < 11;i++){
        ans += item[i]/2;
        leave += item[i]%2;
    }
    ans += leave/4;
    cout << ans << endl;
    return 0;
}