#include<iostream>
#include<string>
#include<algorithm>
#include<cctype>
#include<set>
#include<bitset>
#include<math.h>
#include<map>
#include<queue>
#include<iomanip>
using namespace std;

int main(){
    int n, ans = 0, cnt = 0;
    vector<int> item(11);
    cin >> n;
    for (int i = 0; i < n; i++){    
        for (int j = 0; j < 3; j++){
            int temp;
            cin >> temp;
            if (item[temp]){
                ans++;
                item[temp] = 0;
            } else item[temp]++;
        }
    }
    for (int i = 0; i < 11; i++) cnt += item[i];
    ans += cnt/4;
    cout << ans << endl;
}