Objective-C: where and how should I declare enums?

Good day, friends. I'm newbie in Objective-C. I'm wanting to use enum in my class and make it public. I've understand how to declare enums (http://stackoverflow.com/questions/1662183/using-enum-in-objective-c), but I don't understand where should I declare them.

I've tried:

@interface MyFirstClass : NSObject {
typedef enum myTypes {VALUE_A, VALUE_B, VALUE_C} MyTypes;
}

or:

@interface MyFirstClass : NSObject {
@public
   typedef enum myTypes {VALUE_A, VALUE_B, VALUE_C} MyTypes;
}

But compiler throws error: "expected specifier-qualifier-list before typedef".

What's wrong?