package main

import (
    "fmt"
)

func main(){
    var n int
    fmt.Scan(&n)
    m := make([]int, 10)
    var a, b, c int
    for i := 0; i < n; i++ {
        fmt.Scan(&a, &b, &c)
        m[a - 1] += 1
        m[b - 1] += 1
        m[c - 1] += 1
    }

    var two, four, cnt int
    for _, v := range m {
        if v >= 2 {
            two += v / 2
            cnt += v - (v / 2) * 2
        } else {
            cnt += v
        }
        if cnt >= 4 {
            four++
            cnt = cnt - 4
        }
    }
    fmt.Println(two + four)
}