How to allow user to input new values in a if statment

I would like for someone to help me by telling me what code i should use in case the input number turns out to be for the secound if or third if, if the used doesnt put the right amount (73-77) then id like the user to be able to type in a new value i can use... how do i do that please

namespace test { class Program {

    public static int FahrToCels(int fahr)
    {

        int cel = (fahr - 32) * 5 / 9;
        return cel;
    }

    static void Main(string[] args)
    {
        
        Console.WriteLine("Skrive in Temperaturen: ");
        int fahrenheit = int.Parse(Console.ReadLine());
        
        int celsius = FahrToCels(fahrenheit);
                    
        Console.Write("Presifs any key to continue . . .");
        Console.ReadKey(true);

        do
            if (celsius >= 73 && celsius <= 77)
            {

                Console.WriteLine("now it works ");
                
            }
            else  if (celsius < 72)
            {

                Console.WriteLine("");

               
            }

            else if (celsius > 77)
            {

                Console.WriteLine("");
                
            }





        while (true);

    }
}

}