title: How to put string into string after specific string
body: <p>I am new in programming. I have string <code>NSString *string = @"\U0420\U043e\U0437\U044b";</code> and after each slash<code>('\')</code> i need put another slash to get string like this <code>@"\\U0420\\U043e\\U0437\\U044b"</code></p>
  
  <p>I am new to programming and objective-c. please help.</p>