#include <bits/stdc++.h>
using namespace std;

signed main(){
  int N; cin >> N;
  vector< int > cnt( 10 + 1 );
  for( int i = 0; i < N; ++i ){
    int A, B, C; cin >> A >> B >> C;
    ++cnt[ A ], ++cnt[ B ], ++cnt[ C ];
  }
  int ans = 0, used = 0;
  for( int i = 1; i <= 10; ++i )
    ans += cnt[ i ] / 2, used += cnt[ i ] / 2 * 2, cnt[ i ] = cnt[ i ] / 2 * 2;
  ans += ( N * 3 - used ) / 4;
  cout << ans << endl;
  return 0;
}