using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        string s = "{\"owa_1\":null}";

        Console.WriteLine(s);

        if (s.Contains("owa_1\":null"))

            {

                Console.WriteLine("that matched");

            }

        if (s.Contains(@"owa_1"":null"))

            {

                Console.WriteLine("that matched too");

            }

        if (s.Contains(@"owa_1\"":null"))

            {

                Console.WriteLine("that matched three");

            }

    }

}