title: Weird Regex behavior in C#
body: <p>I am trying to extract some alfanumeric expressions out of a longer word in C# using regular expressions. For example I have the word "FooNo12Bee". I use the the following regular expression code, which returns me two matches, "No12" and "No" as results:</p>
  
  <pre><code>alfaNumericWord = "FooNo12Bee";
  Match m = Regex.Match(alfaNumericWord, @"(No|Num)\d{1,3}");
  </code></pre>
  
  <p>If I use the following expression, without paranthesis and without any alternative for "No" it works the way I am expecting, it returns only "No12":</p>
  
  <pre><code>alfaNumericWord = "FooNo12Bee";
  Match m = Regex.Match(alfaNumericWord, @"No\d{1,3}");
  </code></pre>
  
  <p>What is the difference between these two expressions, why using paranthesis results in a redundant result for "No"?</p>