package main

import "fmt"

func main() {
	var N int
	fmt.Scan(&N)
	items := make([]int, 10)
	for i := 0; i < N; i++ {
		var a, b, c int
		fmt.Scan(&a, &b, &c)
		a--
		b--
		c--
		items[a]++
		items[b]++
		items[c]++
	}
	ans := 0
	rem := 0
	for i := 0; i < len(items); i++ {
		ans += items[i] / 2
		rem += items[i] % 2
	}
	fmt.Println(ans + rem/4)
}