#include <iostream>
#include <sstream>
#include <math.h>
#include <vector>
#include <array>
#include <algorithm>
#include <queue>
#include <numeric>
#include <map>
#include <set>
#include <bitset>

using namespace std;
#define int long long
#define FOR(i, a, b) for(int i=(a);i<(b);i++)
#define RFOR(i, a, b) for(int i=(b-1);i>=(a);i--)
#define REP(i, n) for(int i=0; i<(n); i++)
#define RREP(i, n) for(int i=(n-1); i>=0; i--)
#define ALL(a) (a).begin(),(a).end()
#define UNIQUE_SORT(l) sort(ALL(l)); l.erase(unique(ALL(l)), l.end());
#define CONTAIN(a, b) find(ALL(a), (b)) != (a).end()
#define SUM(a) accumulate(ALL(a), 0)
#define array2(type, x, y) array<array<type, y>, x>
#define vector2(type) vector<vector<type> >
#define out(...) printf(__VA_ARGS__)

/*================================*/

int N;
vector<int> A(10, 0);

signed main()
{
    cin >> N;
    int a, b, c;
    REP(i,N) {
        cin >> a >> b >> c;
        A[a-1]++;
        A[b-1]++;
        A[c-1]++;
    }
    int cnt = 0;
    while (true) {
        sort(ALL(A));
        if (A[9] >= 2) {
            A[9] -= 2;
            cnt++;
        } else {
            int s = SUM(A);
            cnt += s / 4;
            break;
        }
    }

    cout << cnt << endl;

    return 0;
}