public class Lecture
{
    public static void main(String[] args)
    {
        double[][] simul = {
            {3, 2, -1, 4.5},
            {2.5, -1, 0, 1.7, 1, 1, 1, 1},
            {1, 1, 1, 6}
        };          
        
        System.out.println(simul[1][1]);
        
        System.out.println("Sum = " + sum(simul));
    }
    
    public static double sum(double[][] matrix)
    {
        double sum = 0.0;
        
        for(int row = 0; row < matrix.length; row++)
        {
            for(int col = 0; col < matrix[row].length; col++)
            {
                sum += matrix[row][col];
            }
        }
        
        return sum;
    }
}