Task

import java.util.*;

public class Main
{
    public static void main(String[] args)
    {
        final double MAX = 20.0;

        Scanner input = new Scanner(System.in);
        int n = input.nextInt();
        double[][] array = new double[n][n];

        for (int i = 0; i < n; i++){
            for (int j = 0; j < n; j++){
                array[i][j] = Math.random() * 10;
                System.out.print(array[i][j] + " ");
            }
            System.out.println();
        }

        double diagSummary = 0;
        double result = 0;
        int isUpper = 0;
        for (int i = 0; i < n; i++){
            diagSummary += array[i][i];
            if (diagSummary > MAX) isUpper = 1;
        }

        int index = 1;
        for (int j = 0; j < n - 1; j++){
            int k = index;
            do{
                switch(isUpper){
                    case 0: result += array[k][j];
                        break;
                    case 1: result += array[j][k];
                        break;
                }
                k++;
            }while (k < n);
            index++;
        }
        System.out.println("result: " + result);
    }
}