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  1. using System;
  2. using System.Text.RegularExpressions;
  3.  
  4. public class Test
  5. {
  6. 	public static void Main()
  7. 	{
  8. 	    string s = "123456789";
  9.             s = Regex.Replace(s, @"\d{3}(?=\d)", "$0-");
  10.             Console.WriteLine(s);
  11. 	}
  12. }
Success #stdin #stdout 0.05s 37256KB
comments (?)
stdin 
Standard input is empty
stdout 
123-456-789
https://ideone.com/OohJO
language:
C# (gmcs 5.20.1)
created:
12 years ago
visibility:
secret

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