#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int a[334], N, p, b;

int main()
{
    int ans = 0;
    cin >> N;
    b = 3 * N;
    for (int i = 0; i < 3 * N; i++)
    {
        cin >> p;
        a[p]++;
        if (a[p] == 2)
            ans++, a[p] -= 2, b -= 2;
    }
    cout << ans + b / 4 << endl;
}