Hi Uli,
1) Create a formula with this code and place this on the details section:
WhileprintingRecords;
Numbervar count;
shared stringvar array str;
If ({ZCR0000000000310577027.PSP-Element (Stufe1)\PSP-Element (Stufe1) - PSP-Element (Stufe1) (Schlüssel)}
IN shared stringvar array str) then
count := count + 1;
"";
2) create another formula with thise code and place this on the footer:
Whileprintingrecords;
Numbervar count;
-Abhilash