- using System; 
- using System.Text.RegularExpressions; 
-   
- public class Test 
- { 
- 	public static void Main() 
- 	{ 
- 		var result = Regex.Replace(_input, @"<(?<close>/?)((?!img|br).)*?>", @"<${close}p>"); 
- 		Console.WriteLine(result); 
- 	} 
-   
- 	private static string _input = 
- @" 
- <em></ em >  
- <font style=""text-align:justify;"">aaaaaaaaaaa</font> 
- <img src=""abc.jpg""/> 
- <iframe src=""somelink.com"">  
- </iframe> 
- <br> 
- <br/> 
- "; 
- } 
				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