#include <algorithm>
#include <cmath>
#include <cstdio>
#include <deque>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>

using namespace std;

typedef long long ll;

#define MOD 1000000007

int main() {
  int n;
  cin >> n;
  vector<int> cnt(10);
  for (int i = 0; i < n; ++i) {
    int a, b, c;
    cin >> a >> b >> c;
    a--, b--, c--;
    cnt[a]++, cnt[b]++, cnt[c]++;
  }
  int ans = 0;
  int sum = 0;
  for (int i = 0; i < 10; ++i) {
    int t = cnt[i] / 2;
    ans += t;
    cnt[i] -= 2 * t;
    sum += cnt[i];
  }
  ans += sum / 4;
  cout << ans << endl;
  return 0;
}