#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(void)
{
    int defeatenemytimes,a,b,c;
    int itemnumber[20]={};
    scanf("%d",&defeatenemytimes);
    for(int i=0;i<defeatenemytimes;i++)
    {
        scanf("%d %d %d",&a,&b,&c);
        itemnumber[a]++;
        itemnumber[b]++;
        itemnumber[c]++;
    }
    int powupcnt = 0;
    int itemcnt = 0;
    for(int i=1;i<=10;i++)
    {
        powupcnt+=itemnumber[i]/2;
        itemcnt+=itemnumber[i]%2;
        if(itemcnt>=4)
        {
            powupcnt++;
            itemcnt=0;
        }
    }
    printf("%d",powupcnt);
}