#include <bits/stdc++.h>

using namespace std;

int main() {
    int n;
    cin >> n;

    vector<int> vt(10, 0);
    for (int i = 0; i < n; ++i) {
        int a, b, c;
        cin >> a >> b >> c;

        vt[--a]++;
        vt[--b]++;
        vt[--c]++;
    }

    int ans1 = 0, ans2 = 0;
    for (int i = 0; i < 10; ++i) {
        ans1 += vt[i] / 2;
        ans2 += vt[i] % 2;
    }

    cout << ans1 + ans2 / 4 << endl;
    return 0;
}