#include <stdio.h>
int main(){
int n,a[10]={},t,i=10,s=0;
scanf("%d",&n);n*=3;
while(n--){scanf("%d",&t);a[t-1]++;}t=0;
while(i--){s+=a[i]/2;t+=a[i]&1;}
printf("%d",s+t/4);
return 0;
}