using System;
using System.Linq;
using System.Collections.Generic;

public class Test
{

public enum DaysInWeekIds : short
    {
        M = 1,
        Tu = 2,
        W = 4,
        Th = 8,
        F = 16,
        Sa = 32,
        Su = 64
    }
	public static void Main()
	{
    IEnumerable<DaysInWeekIds> daysOfWeek = new DaysInWeekIds[] {DaysInWeekIds.M,DaysInWeekIds.Th,DaysInWeekIds.F};
var res = (DaysInWeekIds)Enum.Parse(
    typeof(DaysInWeekIds)
,   string.Join(",", daysOfWeek.Select(d => d.ToString()).ToArray())
);
Console.WriteLine(res);
	}
}