package main

import (
	"fmt"
)

func main() {
	var n int
	fmt.Scan(&n)
	card := make([]int, 11)
	var c, p int
	for i := 0; i < n; i++ {
		for j := 0; j < 3; j++ {
			fmt.Scan(&c)
			if card[c] == 0 {
				card[c] += 1
			} else {
				card[c] = 0
				p += 1
			}
		}
	}
	count := 0
	for i := 0; i < 11; i++ {
		count += 1 * card[i]
	}
	fmt.Println(p + count/4)
}