Each row has as many elements as defined by the attribute-names line, plus 2 optional as described later. In case there are no attribute-names given, the number of elements is not limited. At the end of each row, 2 additional numbers may be placed, which represent the location of the actor. If no coordinates are given YSOCNET will place them in a specific order. Otherwise coordinates must be assigned to every actor. The first attribute in the row may not start with a number, and should be a unique identifier for each actor, as it is the default attribute to be listed.