C# Extracting a name from a string

static string ParseName(string arg) {
    var regex = new Regex(@"^OU=([a-zA-Z\]+,s+[a-zA-Z\]+),.*$");
    var match = regex.Match(arg);
    return match.Groups[1].Value;
}

string input = @"OU=James, Brown,OU=Test,DC=Internal,DC=Net";
Match m = Regex.Match(input, "^OU=(.*?),OU=.*$");
Console.WriteLine(m.Groups[1].Value);

string name = @"OU=James, Brown,OU=Test,DC=Internal,DC=Net";
string[] splitUp = name.Split("=".ToCharArray(),3);
string namePart = splitUp[1].Replace(",OU","");
Console.WriteLine(namePart);

string line = GetStringFromWherever();

int start = line.IndexOf("=") + 1;//+1 to get start of name
int end = line.IndexOf("OU=",start) -1; //-1 to remove comma

string name = line.Substring(start, end - start);

Regex rx = new Regex(@"(?<!\),");
    String test = "OU=James\, Brown,OU=Test,DC=Internal,DC=Net";
    String[] segments = rx.Split(test);

String name = segments[0].Split('=', 2)[1];

string originalStr = @"OU=James, Brown,OU=Test,DC=Internal,DC=Net";
string replacedStr = originalStr.Replace(",", "&#44;");

string name = replacedStr.Substring(0, replacedStr.IndexOf(","));
Console.WriteLine(name.Replace("&#44;", ","));