using System;

public class Program

{

    public static void Main()

    {

        EnumType et = EnumType.Created | EnumType.Completed;

        Console.WriteLine(GetMaxSetFlagValue(et));

        Console.WriteLine("Hello World");

    }

    public enum EnumType : uint{

        Created = 1,

        Completed = 2,

        Deleted = 4

    }

    static readonly uint maxBit = ((uint)0x1 << (sizeof(uint)-1));

​

    public static EnumType GetMaxSetFlagValue(EnumType input){

        uint n = (uint)input;

        uint i = maxBit;

        while(i>0){

            if((i & n) == i){

               return (EnumType)i;

            }

            i = i >> 1;

        }

        throw new InvalidOperationException();

    } 

​

}