str = @"abc ""def"" ghi """"jkl"""" mn";

namespace ConsoleQuotes

{

    class Program

    {

        static void Main(string[] args)

        {

            string str = @"abc ""def"" ghi """"jkl"""" mn";

            Console.WriteLine(str);

            //abc "def" ghi ""jkl"" mn

        }

    }

}