#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef pair<int,int> P;
 
const int INF = 1e9;
const int mod = 1e9+7;
const double EPS = 1e-10;
const double PI = acos(-1.0);

int main()
{
    int n;
    cin >> n;
    vector<int> abc(10,0);
    for(int i = 0; i < n; i++){
        int a,b,c;
        cin >> a >> b >> c;
        abc[a-1]++;
        abc[b-1]++;
        abc[c-1]++;
    }
    int sum = 0,res = 0;
    for(int i = 0; i < 10; i++){
        sum += abc[i] / 2;
        res += abc[i] % 2;
    }
    cout << sum + res / 4 << endl;

    return 0;
}