using System;
using System.Text.RegularExpressions;
 
public class Test
{
	public static void Main()
	{
    Regex rx = new Regex("^([A-Z]+[1-9][0-9]*(:[A-Z]+[1-9][0-9]*)?(,(?!$)|$))*$");
    Console.WriteLine(rx.IsMatch(""));
    Console.WriteLine(rx.IsMatch("C5:H6,J5:P6,R5:DM6,C15"));
    Console.WriteLine(rx.IsMatch("J6:P6"));
    Console.WriteLine(rx.IsMatch("C5:H6,J5:P6,R5:DM6,C15,"));
    Console.WriteLine(rx.IsMatch("C5:H65:H12,P6,R5:DM6,C15"));
	}
}

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