题解 | #组队竞赛#

public class Main{
    public static void main(String[]args){
        Scanner scan=new Scanner(System.in);
        while(scan.hasNext()){
            int n=scan.nextInt();
            int[]arr=new int[3*n];
            for(int i=0;i<arr.length;i++){
                arr[i]=scan.nextInt();
            }
            Arrays.sort(arr);
            long sum=0;
            for(int i=0;i<n;i++){
                sum+=arr[arr.length-2*(i+1)];
            }
            System.out.println(sum);

        }
    }
}