#include <bits/stdc++.h>
using namespace std;
typedef unsigned long long ul;
typedef signed long long ll;
ul over = 1000000007;

int main(void)
{
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed;
  int n;
  cin >> n;
  int cnt[10];
  fill(cnt, cnt+10, 0);
  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 rest = 0;
  int ans = 0;
  for (int i = 0; i < 10; ++i) {
    ans += cnt[i]/2;
    rest += cnt[i]%2;
  }
  cout << ans + rest/4 << endl;
  return 0;
}