#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)
#define FOR(i,b,e) for (int i=(int)(b); i<(int)(e); i++)
#define ALL(x) (x).begin(), (x).end()

const double PI = acos(-1);

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  int n;
  cin >> n;
  
  int cnt[11] = {};
  REP (i, n) {
    int a, b, c;
    cin >> a >> b >> c;
    cnt[a]++, cnt[b]++, cnt[c]++;
  }

  int ret = 0;
  int sum = 0;
  for (int i = 1; i <= 10; i++) {
    ret += cnt[i] / 2;
    sum += cnt[i] % 2;
  }

  cout << ret + sum/4 << endl;
  
  return 0;
}