Simple if statement Batch

I tried running the code but it doesn't seem to work. How do I make the code work?

@echo off
SET /P choice= What do you want me to do?:
if %choice%==shutdown (
SET /P time= In how many minutes shall I shut down the computer?: 
set /a "time=%time%*60"
shutdown -s -t "%time%"
) elseif (

)