What does the [Flags] attribute mean for enums in C#?

Hi everyone! I just started learning C# and came across the `[Flags]` attribute before an enum declaration. I saw this code in examples, but I can't understand why it's needed and how to use it correctly. I understand regular enums — they just define named constants: ```csharp enum DayOfWeek { Monday = 1, Tuesday = 2, Wednesday = 3 } ``` But when I see this: ```csharp [Flags] enum Permissions { None = 0, Read = 1, Write = 2, Execute = 4 } ``` I don't understand why `[Flags]` is here and why the values are set as powers of two (1, 2, 4). What's the difference from a regular enum? I tried using such an enum without the attribute — the code seems to work, but I feel like I'm doing something wrong. Can you explain with simple examples?