package main

import (
	"fmt"
)

func resolve(N int, a, b, c []int) int {
	ret := 0
	rest := 0
	L := make([]int, 101)
	for i := 0; i < N; i++ {
		L[a[i]] += 1
		L[b[i]] += 1
		L[c[i]] += 1
	}
	for _, l := range L {
		ret += l / 2
		rest += l % 2
	}
	return ret + rest/4
}

func main() {
	var N int
	fmt.Scanf("%d\n", &N)
	a := make([]int, N)
	b := make([]int, N)
	c := make([]int, N)
	for i := 0; i < N; i++ {
		fmt.Scanf("%d %d %d\n", &a[i], &b[i], &c[i])
	}
	fmt.Println(resolve(N, a, b, c))
}