package main

import (
	"fmt"
)

func main() {
	var N, a, b, c, up, rest int
	fmt.Scanln(&N)
	item := make(map[int]int)
	for i := 0; i < N; i++ {
		fmt.Scanln(&a, &b, &c)
		item[a]++
		item[b]++
		item[c]++
	}
	for k, v := range item {
		up += v / 2
		item[k] = v % 2
	}
	for _, v := range item {
		rest += v
	}
	up += rest / 4
	fmt.Println(up)
}