#include <bits/stdc++.h>
#define PB push_back
#define MP make_pair
#define REP(i,n) for (int i=0;i<(n);i++)
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define ALL(a) (a).begin(),(a).end()
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> P;
const int INF=1e9;
int main(){
      int n,a,b,c,sum,cnt[10];
      cin>>n;
      sum=3*n;
      memset(cnt,0,sizeof(cnt));
      REP(i,n){
            cin>>a>>b>>c;
            a--;b--;c--;
            cnt[a]++;cnt[b]++;cnt[c]++;
      }
      int ans=0;
      REP(i,10){
            ans+=cnt[i]/2;
            cnt[i]%=2;
      }
      ans+=(sum-ans*2)/4;
      cout<<ans<<endl;
}