#include <iostream>
#include <algorithm>
using namespace std;
int main()
{
    int n;
    while (cin>>n) {
        int v[11]={};
        while (n--) {
            int a, b, c; cin>>a>>b>>c;
            ++v[a], ++v[b], ++v[c];
        }
        int res=0, x=0;
        for(int i=1;i<=10;++i) {
            res+=v[i]/2;
            x+=(v[i]%=2);
        }
        res+=x/4;
        cout<<res<<endl;
    }
}