:Main
@echo off
setlocal
setlocal EnableDelayedExpansion
set map=0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ
IF NOT DEFINED Citac (SET Citac=0)
cls
if not %Citac% == 2 goto :Vypis

set "DecIn="
set Citac=0

call :strlen "%mujRetezec01%" LenRet01
call :strlen "%mujRetezec02%" LenRet02
call :strlen "%mujRetezec03%" LenRet03
call :strlen "%mujRetezec04%" LenRet04

if not defined LenRet01 goto :Eof
if not defined LenRet02 goto :Eof
if not defined LenRet03 goto :Eof
if not defined LenRet04 goto :Eof

Set /A LenRet01=LenRet01 * 7192 - 10
Set /A LenRet02=LenRet02 * 8488 + 7
Set /A LenRet03=LenRet03 * 6599 + 20
Set /A LenRet04=LenRet04 * 9756 - 18

call :Dec2Base 16 %LenRet01% BaseOut01
call :Dec2Base 16 %LenRet02% BaseOut02
call :Dec2Base 16 %LenRet03% BaseOut03
call :Dec2Base 16 %LenRet04% BaseOut04

echo GoG code is:=%BaseOut01%-%BaseOut02%-%BaseOut03%-%BaseOut04% :)

endlocal
set Citac=0
SET "mujRetezec01="
SET "mujRetezec02="
SET "mujRetezec03="
SET "mujRetezec04="
goto :eof

:Vypis
echo @echo off
echo setlocal
echo IF NOT DEFINED Citac (SET Citac=0)
echo Set /a Citac=Citac + 1
echo\
echo SET "mujRetezec01=%%mujRetezec01%% skakal pes, pres oves, pres zelenou louku"
echo SET "mujRetezec02=%%mujRetezec02%% pec nam spadla, pec nam spadla, kdopak nam ji opravi"
echo SET "mujRetezec03=%%mujRetezec03%% holka modrooka nesedavej u potoka, holka modrooka nesedavej tam"
echo SET "mujRetezec04=%%mujRetezec04%% okolo hradce, v male zahradce, rostou tam dve ruze"
echo\
echo if %%Citac%% == 1 goto :Konec
echo if %%Citac%% == 2 goto :Main
echo goto :eof
echo\

goto :eof

::-------------------------------------------------------------------------------------
:Dec2Base Base DecIn BaseOut
Setlocal
Echo:%2|findstr /i "^[%map:~0,10%]*$" >Nul 2>&1 ||(Echo invalid char for base 10&Goto :Eof)
set /a Num=%2
set "Ret="

:Dec2BaseLoop
set /a "Digit=Num %% %1"
set /a "Num /= %1"
set Ret=!map:~%Digit%,1!%Ret%
if "%Num%" neq "0" goto :Dec2BaseLoop
Endlocal&Set "%3=%Ret%"&Goto :Eof
::-------------------------------------------------------------------------------------

:Base2Dec Base BaseIn DecBack
Setlocal EnableDelayedExpansion
Set /A "Base=%1,PlaceVal=1,Ret=0"
Echo:%2|findstr /i "^[!map:,%Base%!]*$" >Nul 2>&1 ||(Echo invalid char for base %1&Goto :Eof)
Set Val=%2

:Base2DecLoop
Set "Digit=%Val:~-1%"
If %Digit% Leq 9 goto :Next
For /L %%i in (10,1,%Base%) Do If /i "!Digit!" Equ "!map:~%%i,1!" (Set "Digit=%%i" & Goto :Next )
Echo Something went wrong & Pause

:Next
set /A "Ret+=Digit * PlaceVal,PlaceVal *= Base"
Set "Val=%Val:~0,-1%"
If defined Val goto :Base2DecLoop
Endlocal & Set "%3=%Ret%" & Goto :Eof

:strlen string len
rem SetLocal EnableDelayedExpansion
set "token=#%~1" & set "len=0"
for /L %%A in (12,-1,0) do (
    set/A "len|=1<<%%A"
    for %%B in (!len!) do if "!token:~%%B,1!"=="" set/A "len&=~1<<%%A"
)
EndLocal & set %~2=%len%
exit/B

:Konec