#include <bits/stdc++.h>

using namespace std;

int A[11];

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

    while (N--) {
        int a, b, c; cin >> a >> b >> c;
        A[a]++; A[b]++; A[c]++;
    }

    int ans = 0;
    int sum = 0;

    for (int i = 1; i <= 10; ++i) {
        ans += A[i] / 2;
        A[i] %= 2;
        sum += A[i];
    }

    ans += sum / 4;

    cout << ans << endl;
}