Steps for your work :
1) Fetch the file name from directory.
2) Check whether it contains ard
or not.
3) If yes, then convert the rest of file name without extension to Integer or Long or whatever Number.
If No, go to step 1 to check next file if any.
4) If value of variable and converted number matches, wooohhooo you are done.
Break the loop and do whatever you want.
solved How to check if directory contains file which name contains certain string?