General :: Max Number From The Name Of A File?

I need to get the max number from the name of a file

Formant of the file name:
[a-zA-Z]*_[0-9][0-9]_[A-Z][A-Z].log
Delimiter as underscore '_'

[code]....

known part in the above file name will be GA.log A give directory may or may not contain files in the above format or may contain file other then the above format if so then ignore it.

Eg:-

1) Directory=/tmp/log having below listed files

ant_01_EG.log ant_02_GA.log ant_04_EG.log cvs_01_EG.log cvs_02_GA.log cvs_04_EG.log master_01_GA.log master_03_EG.log master_04_GA.log

[code]....

output=> 06

2) Directory=/tmp/log no files

cmd=> ls *[0-9][0-9]_GA.log 2> /dev/null | awk -F_ '{ print $2}' | sort -nr | head -n1 | awk 'BEGIN { if ($1 >0 ) x=0; else x=1 } END {printf "%02.0f
", $1+1}'

output=> 01

if there are no files the output should be 01 and if file(s) found the output should be next highest number+1, In the above example it is 06 My cmd is bit lenghty. reduce my cmd and it should be in one line.