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

int main() {
  int n,e=0,f=0;cin>>n;
  vector<int> a(n);
  vector<int> b(n);
  vector<int> c(n);
  vector<int> d(10);
  for(int i=0;i<n;i++){
    cin>>a[i]>>b[i]>>c[i];
    d[a[i]-1]++;d[b[i]-1]++;d[c[i]-1]++;
  }
  for(int i:d){
    e+=i%2;
    f+=i/2;
  }
  cout<<e/4+f<<endl;
  return 0;
}