Does not work Regex.Match C#. What is the error?

Using a string of letters and part of this string is not to be disclosed without the brackets. This line can be reduce the type of "(3A)" what is perceived as "AAA". This should make method.
The fact is that when searching using Regex.Match returns a blank. And for some reason can not understand.
So, somehow, Replace the brackets are ignoring me and are not removed (they are in target)
static string Zamena(string stroka,string target) // stroka - input string in which it is necessary to reveal target
 string to_replace= ""; // something that will eventually be replaced by target
 celb string = ""; 
 Match find = Regex.Match(stroka, @"([0-9]*)");
 int kolvo = Convert.ToInt32(find.Groups[1].Value); // number of repetitions
 find = Regex.Match(stroka, @"(\w*)");
 celb = find.Groups[1].Value; // what is repeated
 for (int i = 1;i<=kolvo;i++)
 to_replace += celb;
 stroka = Regex.Replace(stroka, target,to_replace);
 return stroka;
April 3rd 20 at 17:40
1 answer
April 3rd 20 at 17:42
Thanks, understood, to sum up:
1) If you want to remove parenthesis using Regex.Replace parameters pattern you need to add:

Accordingly, the final pattern:
@"\(" + "some default expression" + @"\)"

Brackets in the default expression (if they are around) will be ignored
2) I do Not understand why, but the template brackets of the regular expression are working correctly. You must be stupid to highlight each bracket, which can meet

Find more questions by tags Regular expressionsC#