#include <stdio.h>
int main(){
    //input
    int N;
    scanf("%d",&N);

    int itemCount[10] = {0};
    for (int i = 0;i < N;i++){
        int a,b,c;
        scanf("%d %d %d",&a,&b,&c);
        itemCount[a-1]++;
        itemCount[b-1]++;
        itemCount[c-1]++;
    }

    //calculate power up count
    int puCount = 0;
    int oddCount = 0;
    for (int i = 0;i < 10;i++){
        if (itemCount[i]%2 == 0){
            puCount += itemCount[i]/2;
        }else{
            puCount += (itemCount[i]-1)/2;
            oddCount++;
        }
    }
    puCount += (oddCount-oddCount%4)/4;

    //output
    printf("%d\n",puCount);
    return 0;
}