import java.io.*;
import java.util.*;
import java.math.*;

class Main29 {
	
	public static void out (Object out) {
		System.out.println(out);
	}
	
	public static void main (String[] args) throws IOException {
		BufferedReader br = 
			new BufferedReader(new InputStreamReader(System.in));
		
		int ans = 0;
		int n = Integer.parseInt(br.readLine());
		int[] nums = new int[3 * n];
		
		for (int i = 0; i < n; i++) {
			String[] line = br.readLine().split(" ");
			for (int j = 0; j < line.length; j++) {
				nums[i * 3 + j] = Integer.parseInt(line[j]);
			}
		}
		Arrays.sort(nums);
		
		//System.out.println(Arrays.toString(nums));
		
		for (int i = 1; i < nums.length; i++) {
			if (nums[i] == nums[i - 1]) {
				ans++;
				nums[i] = 0;
				nums[i - 1] = 0;
			}
		}
		
		//out(ans);
		out(ans + (3 * n - ans * 2) / 4);
	}
}