#define _GLIBCXX_DEBUG
#define ll long long
#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

void print(auto a){
  cout << a;
}

void printL(auto a){
  cout << a << endl;
}

void fix(int n){
  cout << fixed << setprecision(n);
}

ll RD(ll n, ll m){
  return n/m;
}

void INP(int n, vector<int> &A){
  for(int i = 0; i < 3; i++){
    int a; cin >> a;
    A[a-1]++;
  }
  if(n > 1) INP(n-1, A);
}

void ANS(vector<int> A){
  int ans = 0, mod = 0;
  for(int i = 0; i < (int)A.size(); i++){
    ans += A[i]/2;
    mod += A[i]%2;
  }
  ans += mod/4;
  printL(ans);
}

int main(){
  int N; cin >> N;
  vector<int> A(10, 0);
  INP(N, A);
  ANS(A);
}