#include <iostream>
using namespace std;
int main(){
    int N,a,b,c,kind[10]={0},cnt=0,ans=0;
    cin >> N;
    for(int i=0;i<N;i++){
        cin >> a >> b >> c;
        kind[a-1]++;kind[b-1]++;kind[c-1]++;
    }
    for(int i=0;i<10;i++){
        ans+=kind[i]/2;cnt+=kind[i]%2;
    }
    ans+=cnt/4;
    cout << ans << endl;
    return 0;
}