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

int main(void){
    int i,a,b,c,N;
    int count[11]={0};  // count[0]にパワーアップ回数を格納
    int sum = 0;    // 余り用

    scanf("%d",&N);
    for(i=0; i<N; i++) {
        scanf("%d %d %d",&a,&b,&c);
        count[a]++;
        count[b]++;
        count[c]++;
    }

    for(i=1; i<=10; i++){
        while(count[i]>=2){
            count[i] -= 2;
            count[0]++;        
        }
        sum += count[i];
    }

    printf("%d",sum/4 + count[0]);
    return 0;
}