Get min and max value in column

Gents,

I have a big file file like this.

The file is sorted and I would like to find the min and max value, taking in the consideration key1 (substr$0,1,5) and key2 substr($0,6,5)

I would like to get something like this

Thanks for your help

Moderator's Comments:

Please wrap all code, files, input & output/errors in CODE tags It makes them easier to read and preserves multiple spaces in case they are important.