Deleting files older than a month

Need to delete all sub-directories which are a month old. But last day of the month data should be ignored for previous three months.

The data representation is as follows:

bkp_01102014 bkp_04102014 bkp_07102014 bkp_11102014 bkp_15112014

................... ................... bkp_24112014 bkp_27112014 bkp_30062014 bkp_31072 bkp_20092014

How to automate this using find or any other command.