#include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <sstream>
#include <string>
#include <cstdlib>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <limits>
#include <complex>
#include <functional>
using namespace std;
#define rep(i,n) for (int (i)=0;(i)<(int)(n);++(i))

int num[10];

int main() {
    int n, ans = 0; cin >> n;
    rep(i, n) {
        rep(j, 3) {
            int id;
            cin >> id; id--;
            num[id]++;
        }
    }
    int t = 0;
    rep(i, 10) {
        ans += num[i]/2;
        t += num[i]%2;
    }
    ans += t/4;
    cout << ans << endl;
}