#include <bits/stdc++.h>

using namespace std;

#define REP(i,a,b) for(int i=a;i<(int)b;i++)
#define rep(i,n) REP(i,0,n)

int main() {
  
  int N; cin >> N;
  vector<int> items(10);
  rep(_, N) {
    int a, b, c;
    cin >> a >> b >> c; a--, b--, c--;
    items[a] ++, items[b] ++, items[c] ++;
  }
  
  int ans = 0;
  int remain = 0;
  rep(i, 10) {
    ans += items[i] / 2;
    remain += items[i] % 2;
  }
  ans += remain / 4;
  
  cout << ans << endl;
  
  return 0;
}