#include<iostream>
using
namespace
std;int
main() {
int
a[11]={};
int n;cin>>n;
int aa;
for(int
i=0;i<3*
n;i++)
{
cin>>
aa;a[aa]
++;
}
int
sum=0,all
=0;for(int
i=1;i<=
10;i++){
sum+=a[i]
/2;all
+=a[i]
%2;
}
cout<<sum
+all/4<<
endl;
return
0;
}