public static void main(String[] args) {

  //z,x
  int [][] matrix = new int[][]{{2,1},{3,4}};
  int result = matrixCalculation(matrix);
  System.out.println(result);

}

private static int matrixCalculation(int[][] matrix) {
  int result = 0;
  for(int i=0;i<matrix.length;i++) {
    int[] row = matrix[i];
      for (int j : row) {
        result += j;
      }
    }

  return result;
}