How To Print Double Inverted Comma (") in C#

This is a console program to accept a string and print it with double inverted comma. 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace hello
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Enter a string");
string str = Console.ReadLine();
Program pbj = new Program();
str = pbj.convertto_inverted(str);
Console.WriteLine(str);
Console.ReadKey();
}
public string convertto_inverted(string str)
{
string comma = "";
comma = "\"" + str + "\"";
return comma;
}
}
}