import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class CheckGraphConstuction
{
    public static Integer sum(List<Integer> list)
    {
        Integer sum = 0;
        for (Integer integer : list)
            {
                sum += integer;
            }
        return sum;
    }

    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter the number of vertices: ");
        Integer n = sc.nextInt();
        System.out
        .println("Enter the Degree Sequence: <Degree sequence is always in non-increasing order>");
        List<Integer> sequence = new ArrayList<Integer>();
        while (n > 0)
            {
                sequence.add(sc.nextInt());
                n--;
            }
        System.out.println(sequence.toString());
        if (sum(sequence) % 2 == 0)
            {
                System.out
                .println("Graph can be constructed using the given sequence G=("
                         + sequence.size()
                         + ", "
                         + (sum(sequence) / 2)
                         + ").");
            }
        sc.close();
    }
}

/*

Enter the number of vertices:
7
Enter the Degree Sequence: <Degree sequence is always in non-increasing order>
5 3 3 2 2 1 0
[5, 3, 3, 2, 2, 1, 0]
Graph can be constructed using the given sequence G=(7, 8).

Enter the number of vertices:
3
Enter the Degree Sequence: <Degree sequence is always in non-increasing order>
3 3 1
[3, 3, 1]
no soultion exists.