title: Regex .NET: insert character in start of string if not a specific character
body: <p>New to Regex so bear with me.  I want to insert an "H" at the beginning of a string if the first character is not an "H".  If it is an "H" then I would leave it alone.  I'm working under Regex .net  </p>
  
  <p>For example...</p>
  
  <p>Input H123456789
  Ouput H123456789</p>
  
  <p>Input 123456789
  Output H123456789</p>
  
  <p>Input ABCDE
  Output HABCDE</p>
  
  <p>Thanks</p>
  
  <p>I don't know enough about Regex to include anything helpful here</p>