EndDate := bis;
StartDate := von;
diffDays := (EndDate - StartDate) / 86400 + 1;
strtDay := @Modulo(@Weekday(StartDate); 7);
endDay := @Modulo(@Weekday(EndDate); 7);
result := (diffDays - endDay + strtDay -
* 5 / 7 - @Max(-2; -strtDay) - @Min(1; endDay) + 5 - strtDay + endDay;
@If(@IsError(result);"";result)