#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); i++)
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<ll> vll;
typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef vector<vector<ll>> vvll;
const ll inf = 1e16;
const ll md = 1000000007;

int main() {
  int n;
  cin>>n;
  vi cnt(10);
  rep(i,n){
    int a,b,c;
    cin>>a>>b>>c;
    cnt[a-1]++;
    cnt[b-1]++;
    cnt[c-1]++;
  }
  int ans=0;
  int r=0;
  rep(i,10){
    ans+=cnt[i]/2;
    r+=cnt[i]%2;
  }
  ans+=r/4;
  cout<<ans<<endl;
  return 0;
}