#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < n; ++i)
typedef long long ll;
using namespace std;

int main() {
    cin.tie(0)->sync_with_stdio(0);

    int N;
    cin >> N;
    vector<int> cnt(11);
    rep(i, N) {
        rep(j, 3) {
            int a;
            cin >> a;
            cnt[a]++;
        }
    }

    int ans = 0;
    rep(i, 11) {
        ans += cnt[i] / 2;
        cnt[i] %= 2;
    }

    int sum = accumulate(cnt.begin(), cnt.end(), 0);
    ans += sum / 4;
    cout << ans << "\n";

    return 0;
}