#include <iostream>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <algorithm>
#include <cstring>
#include <cstdio>
#include <fstream>
#include <sstream>
using namespace std;
typedef long long ll;

int cnt[20];

int main(){
    int N;
    cin >> N;
    
    for(int i=0;i<N;i++){
        int a, b, c;
        cin >> a >> b >> c;
        
        cnt[a]++;
        cnt[b]++;
        cnt[c]++;
    }
    
    int res = 0;
    int rest = 0;
    
    for(int i=1;i<=10;i++){
        res += cnt[i] / 2;
        rest += cnt[i] % 2;
    }
    
    res += rest / 4;
    cout << res << endl;
    
    return 0;
}