debugging error

I was trying to program a prime number detector, pretty close to success. Here is my code, along with the error by the compiler, which I can't figure what it means. using System; public class Program { public static void Main() { string Input(){ string input = Console.ReadLine()...

Greetings, I am completely new to programming and also to C#. I'm working out of a book called "Beginning C# 6 Programming with Visual Studio 2015". There is an example that I'm having trouble de-bugging and I swear I have typed everything exactly as in the book! but perhaps I'm missing...