renaming files with repeating numbers 1-3

[keon]

Hi,

Because of an much easier further processing of some photos, i need to add a repeating number prefix to all files of a folder.

I'd like the files to look like this:

1_test1.jpg
2_test2.jpg
3_test3.jpg
1_test4.jpg
2_test5.jpg
3_test6.jpg
1_test7.jpg

Does anybode know a way or programm to do that?

thanks,
kathi