public static void Main()
Console.WriteLine("Level Calculator");
Console.WriteLine("Enter Grade as Percent");
double mark = Convert.ToDouble(Console.ReadLine());
Console.WriteLine("Your corresponding level is: 4+");
Console.WriteLine("Your corresponding level is: 4");
Console.WriteLine("Your corresponding level is: 4-");
Console.WriteLine("Your corresponding level is: 3+");
Console.WriteLine("Your corresponding level is: 3");
Console.WriteLine("Your corresponding level is: 3-");
Console.WriteLine("Your corresponding level is: 2+");
Console.WriteLine("Your corresponding level is: 2");
Console.WriteLine("Your corresponding level is: 2-");
Console.WriteLine("Your corresponding level is: 1+");
Console.WriteLine("Your corresponding level is: 1");
Console.WriteLine("Your corresponding level is: 1-");
Console.WriteLine("Your corresponding level is: R");