China DOS Union

Help:
How can I batch rename files inside folders using the folder name?
For example, folder f contains three folders: a, b, and c. Folder a contains two files, x and y; folder b contains three files, m, n, and s; folder c contains one file, k. How can I use a batch file to rename
the two files x and y in folder a under folder f to a1 and a2, rename the three files m, n, and s in folder b to b1, b2, and b3, and rename file k in folder c to c?

Solved already
@echo off
for /d %%i in (*) do (
call :rm "%%i"
)
pause
goto :eof

:rm
set num=0
for /r %1 %%a in (*.*) do (
set /a num+=1
call ren "%%a" "%~1%%num%%%%~xa"
)