package main

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

func nextInt(sc *bufio.Scanner) int {
	sc.Scan()
	i, err := strconv.Atoi(sc.Text())
	if err != nil {
		log.Fatal(err)
	}
	return i
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n := nextInt(sc)
	var counter [11]int
	for i := 0; i < n*3; i++ {
		counter[nextInt(sc)] += 1
	}

	powerUp := 0
	remaining := 0
	for _, c := range counter {
		powerUp += c / 2
		remaining += c % 2
	}
	powerUp += remaining / 4

	fmt.Println(powerUp)
}