You can also write an extension method for this
public static string Right(this string s, int length)
{
length = Math.Max(length, 0);
if (s.Length > length)
{
return s.Substring(s.Length - length, length);
}
else
{
return s;
}
}
And then you can do
var result = "Formandmanner.AAA".Right(4);