DefData, ReadData... help.

Using ReadData how can I read a specific cell?

Example

#setting
DefData 0,2,3,5,6

Let's say I wana read the 5th cell, what would you do.

Basicly Im trying to access #map_main_data get 3rd/4th cell which is 10 to determine how many cells horizontal and then vertical #map_main_layer1 has.

#map_main_data
DefData 32,32,10,10,2

#map_main_layer1

DefData 0,0,0,0,0,0,0,0,0,0
DefData 0,0,0,0,0,0,0,0,0,0
DefData 0,0,0,0,0,0,0,0,0,0
DefData 0,0,0,0,0,0,0,0,0,0
DefData 0,0,0,0,0,0,0,0,0,0
DefData 0,0,0,0,0,0,0,0,0,0
DefData 0,0,0,0,0,0,0,0,0,0
DefData 0,0,0,0,0,0,0,0,0,0
DefData 0,0,0,0,0,0,0,0,0,0
DefData 0,0,0,0,0,0,0,0,0,0