using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("What size of pizza do you want?");

string sizeInput = Console.ReadLine();

​

double size;

​

while (true) {

    if (sizeInput.Substring(0, 1).ToUpper() == "S") {

        size = 8;

        break;

    }

    else if (sizeInput.Substring(0, 1).ToUpper() == "M") {

        size = 10;

        break;

    }

    else if (sizeInput.Substring(0, 1).ToUpper() == "L") {

        size = 12;

        break;

    }

    else {

        Console.WriteLine("Please input: 1, 2, or 3");

        sizeInput = Console.ReadLine(); 

    }

}

​

    }

}