@echo off&setlocal ENABLEDELAYEDEXPANSION
set code=ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=
set /p num=input:
set num1=%num:~0,2%
set num2=%num:~2,2%
set num3=%num:~4,2%
set /a num1=0x%num1%
set /a num2=0x%num2%
set /a num3=0x%num3%
set /a "T1=(%num1%&252)>>2"
set /a "T2=((%num1%&3)<<4)+((%num2%&240)>>4)"
set /a "T3=((%num2%&15)<<2)+((%num3%&192)>>6)"
set /a "T4=(%num3%&63)"
echo code:!code:~%T1%,1!,!code:~%T2%,1!,!code:~%T3%,1!,!code:~%T4%,1!
pause>nul
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