//No.29 パワーアップ

import java.util.*;
import java.io.*;
import static java.util.Arrays.*;
import static java.lang.Math.*;

public class No29 {
    
    static final Scanner sc = new Scanner(System.in);
    static final PrintWriter out = new PrintWriter(System.out,false);

    static void solve() {
        int n = sc.nextInt();
        int[] a = new int[10];
        for (int i=0; i<n; i++) {
            for (int j=0; j<3; j++) {
                a[sc.nextInt()-1]++;
            }
        }
        int cnt = 0, t = 0;
        for (int i=0; i<10; i++) {
            while (a[i] >= 2) {
                a[i] -= 2;
                cnt++;
            }
            t += a[i];
        }
        cnt += t/4;
        out.println(cnt);
    }

    public static void main(String[] args) {
        long start = System.currentTimeMillis();

        solve();
        out.flush();

        long end = System.currentTimeMillis();
        //trace(end-start + "ms");
        sc.close();
    }

    static void trace(Object... o) { System.out.println(deepToString(o));}
}