package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

func main() {
	var N int
	fmt.Scan(&N)
	m := map[int]int{
		1:  0,
		2:  0,
		3:  0,
		4:  0,
		5:  0,
		6:  0,
		7:  0,
		8:  0,
		9:  0,
		10: 0,
	}
	pup := 0
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	for i := 0; i < N; i++ {
		for j := 0; j < 3; j++ {
			sc.Scan()
			n, _ := strconv.Atoi(sc.Text())
			if m[n] == 1 {
				pup++
				m[n] = 0
			} else {
				m[n]++
			}
		}
	}
	item := 0
	for _, v := range m {
		item += v
	}
	pup += item / 4
	fmt.Println(pup)
}