Converting MeleeSystem by Brackeys to C# (most likely a silly mistake)

I haven't gotten used to c# syntax or error messages, so this is probably pretty simple to solve. I am trying to replicate the following code in C#:
http://s9.postimg.org/pwco3xt7z/Melee_System_Brackeys.png
(if this link breaks, the video is )

This is my failed attempt:
Converting MeleeSystem by Brackeys to C# (most likely a silly mistake)