/* -*- coding: utf-8 -*-
 *
 * 29.cc: No.29 パワーアップ - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int M = 10;

/* typedef */

/* global variables */

int cs[M];

/* subroutines */

/* main */

int main() {
  int n;
  cin >> n;

  while (n--) {
    for (int i = 0; i < 3; i++) {
      int ai;
      cin >> ai;
      ai--;
      cs[ai]++;
    }
  }

  int cnt = 0, rem = 0;
  for (int i = 0; i < M; i++) {
    cnt += cs[i] / 2;
    rem += cs[i] % 2;
  }
  cnt += rem / 4;

  printf("%d\n", cnt);
  return 0;
}