/*
    No.29 パワーアップ
    https://yukicoder.me/problems/no/29
*/
#include <bits/stdc++.h>
using namespace std;

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

    int item[10] = {0};

    int n;
    cin >> n;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < 3; j++) {
            int idx;
            cin >> idx;
            item[idx - 1] += 1;
        }
    }

    int dup = 0, rest = 0;
    for (int i = 0; i < 10; i++) {
        if (item[i] >= 2) {
            int num = item[i];
            dup += num / 2;
            rest += (num % 2);
        } else {
            rest += item[i];
        }
        // cout << "dup, rest = " << dup << ", " << rest << endl;
    }
    cout << (dup + rest / 4) << endl;
}