package main

import "fmt"

func main() {
	var n int //敵を倒す回数
	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}
	var a, b, c int
	for i := 0; i < n; i++ {
		fmt.Scan(&a, &b, &c)
		m[a]++
		m[b]++
		m[c]++
	}

	ans := 0
	for _, v := range m {
		if int(v/2) > 0 {
			ans += int(v / 2)
		}
	}

	odd := 0
	for _, v := range m {
		if int(v%2) != 0 {
			odd++
		}
	}
	ans += int(odd / 4)
	fmt.Println(ans)
}