#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;

int main() {
    int n; cin >> n;
    vector<int> cnt(11, 0);
    while (n--) {
        int a, b, c; cin >> a >> b >> c;
        cnt[a]++, cnt[b]++, cnt[c]++;
    }
    int ans = 0;
    int rest = 0;
    for (int &ci: cnt) {
        ans += ci / 2, rest += ci %= 2;
    }
    cout << ans + rest / 4 << endl;
    return 0;
}