#include <bits/stdc++.h>

inline long nextInt(void) {
  long temp;
  std::cin >> temp;
  return temp;
}

int main() {

  int N;
  int temp = 0;
  int ans = 0;
  int a, b, c;
  int count[16] = {};

  std::cin >> N;
  for(int i = 0; i < N; ++i) {
    std::cin >> a >> b >> c;
    ++count[a];
    ++count[b];
    ++count[c];
  }

  for(int i = 1; i <= 10; ++i) {
    ans += count[i]/2;
    count[i] %= 2;
  }

  for(int i = 1; i <= 10; ++i) {
    temp += count[i];
  }

  ans += temp / 4;

  std::cout << ans << std::endl;
  
  return 0;
}