#include <iostream>
using namespace std;

void get(int i,int *abc,int *item)
{
    int j;
    for(j = 1; j <= 10; j++){
        if(abc[i] == j){
            item[j-1]++;
            break;
        }
    }
}

int main()
{
    int N;
    cin >> N;
    
    int a[100],b[100],c[100];
    int item[10] = {};
    for(int i = 0; i < N; i++){
        cin >> a[i] >> b[i] >> c[i];
        get(i,a,item);
        get(i,b,item);
        get(i,c,item);
    }
    
    int same = 0,differ= 0;
    for(int i = 0; i <= 9; i++){
        same += item[i] / 2;
        differ += item[i] % 2;
    }

    cout << same + (differ / 4) << endl;

    return 0;
}