#include <stdio.h>
#include <stdlib.h>
int main()
{
  int N;
  int *A;
  scanf("%d", &N);
  A = (int*)malloc(sizeof(int)*N*3);
  int i;
  for (i=0; i<N*3; i++) {
    scanf("%d", &(A[i]));
  }

  int *item = (int*)malloc(sizeof(int)*10);
  for (i=0; i<10; i++) item[i] = 0;
  for (i=0; i<N*3; i++) item[A[i]-1]++;

  int pup = 0;
  int rest = 0;
  for (i=0; i<10; i++) {
    pup += (item[i]/2);
    rest += (item[i]%2);
  }
  pup += (rest/4);

  printf("%d\n", pup);
  return 0;
}