using System;
using System.Text;
using System.Text.RegularExpressions;
using System.Globalization;
using System.Linq;

public class Program
{
	public static void Main()
	{
		string rawInput = "ἀἁἂἃἄἅἆἇὰάᾀᾁᾂᾃᾄᾅᾆᾇᾰᾱᾲᾳᾴᾶᾷᾶ";
		Console.WriteLine(rawInput);
		string normalizedInput = Utility.RemoveDiacritics(rawInput);				

		string pattern = "α+";
        
        var result = Regex.Matches(normalizedInput, pattern);
		if(result.Count > 0)
			Console.WriteLine(result[0]);

	}
}

public static class Utility
{
    public static string RemoveDiacritics(this string str)
    {
        if (null == str) return null;
        var chars =
            from c in str.Normalize(NormalizationForm.FormD).ToCharArray()
            let uc = CharUnicodeInfo.GetUnicodeCategory(c)
            where uc != UnicodeCategory.NonSpacingMark
            select c;

        return new string(chars.ToArray()).Normalize(NormalizationForm.FormC);
    }

}