import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        int N = Integer.parseInt(reader.readLine());
        int[] items = new int[10];

        String[] line;
        for (int i = 0; i < N; i++) {
            line = reader.readLine().split(" ");
            for (int j = 0; j < 3; j++) {
                items[Integer.parseInt(line[j]) - 1] += 1;
            }
        }

        int powerUpTimes = 0;
        int fourItemsLevelUpCounter = 0;
        for (int i = 0; i < 10; i++) {
            while (items[i] >= 2) {
                items[i] -= 2;
                powerUpTimes += 1;
            }
            if (items[i] == 1) {
                fourItemsLevelUpCounter += 1;
            }
        }

        powerUpTimes += (fourItemsLevelUpCounter / 4);

        System.out.println(powerUpTimes);
    }
}