#include <bits/stdc++.h>
using namespace std;

int main() {
int n;
cin>>n;
int z[9]={0};
int a,b,c;
for (int i = 0; i < n; ++i) {
cin>>a>>b>>c;
z[a-1]++;z[b-1]++;z[c-1]++;
}
int tsum=0;
int fsum=0;
for (int j = 0; j < 9; ++j) {
	tsum+=z[j]/2;
	fsum+=z[j]%2;
}
cout<<tsum+fsum/4<<endl;

}