rename pictures in export

hello, how could I rename the photos in the export like this?
folder number _ incremental number of photos in folder.
Numbering starting from one for each folder.
 I use to put first (folder name)_(evaluation) but I could only number them from one to five by putting the stars in every folder. 
So i am able to rename them from 1 to 5. But i need more numbers right now since every folder can contain more pictures.