#include <bits/stdc++.h>

using namespace std;

#define REP(i, n) for(int i = 0; i < n; i++)

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    int n;
    cin >> n;
    vector<int> item(11);
    REP(i, n) {
        int a, b, c;
        cin >> a >> b >> c;
        item[a]++;
        item[b]++;
        item[c]++;
    }

    int ans1 = 0, ans2 = 0;
    REP(i, 11) {
        ans1 += item[i] / 2;
        ans2 += item[i] % 2;
    }
    cout << ans1 + ans2 / 4 << endl;
    return 0;
}