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

public class Main {
    static int[][] dp;
    static Box[] boxes;
    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.parseInt(br.readLine());
        dp = new int[n][n + 1];
        boxes = new Box[n + 1];
        for (int i = 0; i < n; i++) {
            boxes[i] = new Box(br.readLine());
            Arrays.fill(dp[i], -1);
        }
        boxes[n] = new Box(new int[]{Integer.MAX_VALUE, Integer.MAX_VALUE, Integer.MAX_VALUE});
        Arrays.sort(boxes);
        System.out.println(dfw(n - 1, n));
    }
    
    static int dfw(int idx, int bidx) {
        if (idx < 0) {
            return 0;
        }
        if (dp[idx][bidx] != -1) {
            return dp[idx][bidx];
        }
        dp[idx][bidx] = dfw(idx - 1, bidx);
        if (boxes[bidx].smaller(boxes[idx])) {
            dp[idx][bidx] = Math.max(dp[idx][bidx], dfw(idx - 1, idx) + 1);
        }
        return dp[idx][bidx];
    }
    
    static class Box implements Comparable<Box> {
        int[] arr = new int[3];
        
        public Box(int[] arr) {
            this.arr = arr;
            Arrays.sort(arr);
        }
        
        public Box(String line) {
            String[] lines = line.split(" ", 3);
            for (int i = 0; i < 3; i++) {
                arr[i] = Integer.parseInt(lines[i]);
            }
            Arrays.sort(arr);
        }
        
        public int compareTo(Box another) {
            for (int i = 0; i <= 2; i++) {
                if (arr[i] != another.arr[i]) {
                    return arr[i] - another.arr[i];
                }
            }
            return 0;
        }
        
        public boolean equals(Object o) {
            Box another = (Box)o;
            for (int i = 0; i < 3; i++) {
                if (arr[i] != another.arr[i]) {
                    return false;
                }
            }
            return true;
        }
        
        public boolean smaller(Box another) {
            for (int i = 0; i < 3; i++) {
                if (arr[i] <= another.arr[i]) {
                    return false;
                }
            }
            return true;
        }
    }
}