#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]++;
        }
    }
    rep(i, 10) {
        int t = num[i]/2;
        ans += t;
        num[i] -= t*2;
    }
    int cnt = 0;
    rep(i, 10) {
        if (num[i]) cnt++;
        if (cnt == 4) {
            ans++;
            cnt = 0;
        }
    }
    cout << ans << endl;
}