#include <iostream>
#include <vector>
#include <algorithm>
#define REP(i,n) for(int i=0;i<n;i++)
using namespace std;

int items[11];

int main() {
    int n;
    int a, b, c;
    int up, tmp;
    cin >> n;
    REP(i, n) {
        cin >> a >> b >> c;
        items[a]++;
        items[b]++;
        items[c]++;
    }
    REP(i, 11) {
        up += items[i] / 2;
        tmp += items[i] % 2;
    }
    up += tmp / 4;
    cout << up << endl;
    return 0;
}