How to count repeater table row in infopath 2010 using out of box

Following step are using infopath 2010

count(preceding-sibling::my:group10) + 1


- Just add one repeater table in infopath 2010.
- Add two columns  Field 1 and Field 2 in repeater table.
- Click right the field 1 column, then set default value (count(preceding-sibling::my:group10) + 1).
- Just check that and run.