#include <iostream>
#include <vector>

int main() {
    using namespace std;
    int n;
    cin >> n;
    vector<int> count(10, 0);
    while (n--) {
        int a, b, c;
        cin >> a >> b >> c;
        count[a - 1]++;
        count[b - 1]++;
        count[c - 1]++;
    }
    int ans = 0, rem = 0;
    for (int e : count) {
        ans += e / 2;
        rem += e % 2;
    }
    cout << ans + rem / 4 << endl;
}