#include <bits/stdc++.h>
#define rep(i,n)for(long long i=0;i<(n);i++)
using namespace std;
typedef long long ll;
const int MOD=1e9+7;
const int MAX = 1000000;
const ll INF = (1LL << 31) - 1;
const double pi=acos(-1);

int main(){
  int n;
  cin >> n;
  vector<int>vec(10);
  rep(i,n){
    int a,b,c;
    cin >> a >> b >> c;
    a--;
    b--;
    c--;
    vec[a]++;
    vec[b]++;
    vec[c]++;
  }
  int ans=0;
  rep(i,10){
    ans+=vec[i]/2;
    if(vec[i]%2==0)vec[i]=0;
    else vec[i]=1;
  }
  int sum=0;
  rep(i,10){
    sum+=vec[i];
  }
  ans+=sum/4;
  cout << ans << endl;
}