import java.util.*;
import java.math.*;
import java.io.*;
 
public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] sum = new int[10];
		
		for(int i = 0; i < n; i++) {
			for(int j = 0; j < 3; j++) {
				sum[sc.nextInt()-1]++;
			}
		}
		int ans = 0;
		int a = 0;
		for(int i = 0; i < 10; i++) {
			ans += sum[i] / 2;
			a += sum[i] % 2;
		}
		ans += a/4;
		System.out.println(ans);
	}
}