#include <iostream>
using namespace std;

int main(){
    int box[15] = {0};
    
    int n;
    cin >> n;
    
    for(int i = 0; i < n; ++i){
        int a, b, c;
        cin >> a >> b >> c;
        ++box[a];
        ++box[b];
        ++box[c];
    }
    
    int sum = 0;
    for(int i = 1; i <= 10; ++i){
        sum += box[i] / 2;
        box[i] %= 2;
    }
    
    int t_sum = 0;
    for(int i = 1; i <= 10; ++i){
        t_sum += box[i];
    }
    
    sum += t_sum / 4;
    
    cout << sum << endl;
    
    return 0;
}