#include<stdio.h>

int main(void){
  int i;
  int N, a, b, c;
  int S[11] = {};
  int PowerUP = 0, sum = 0;

  scanf("%d", &N);

  for(i = 0; i < N; i++){
    scanf("%d %d %d", &a, &b, &c);
    S[a]++;
    S[b]++;
    S[c]++;
  }
  for(i = 0; i < 11; i++){
    PowerUP += S[i] / 2;
    S[i] = S[i] % 2;
    sum += S[i];
  }
  PowerUP += sum / 4;
  printf("%d\n", PowerUP);
  return 0;
}