public static void Main()
Console.WriteLine("What size of pizza do you want?");
string sizeInput = Console.ReadLine();
if (sizeInput.Substring(0, 1).ToUpper() == "S") {
else if (sizeInput.Substring(0, 1).ToUpper() == "M") {
else if (sizeInput.Substring(0, 1).ToUpper() == "L") {
Console.WriteLine("Please input: 1, 2, or 3");
sizeInput = Console.ReadLine();