using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Please enter the current major you are pursuing.");

        string strMajor = Console.ReadLine();

        Console.WriteLine("Please enter your score in the class.");

        int intScore;

        string strScore = Console.ReadLine();

        bool IsValidNumber = Int32.TryParse(strScore, out intScore);

        bool ValidNumber = intScore >= 0 && intScore <= 100;

        if  (IsValidNumber == false || ValidNumber == false)

        {

            Console.WriteLine("ERROR: Please enter a whole number 0-100 for your score.");

            return;

        }

        else

        { 

            Console.WriteLine("Valid Score Entered");

        }

        string strGrade;

        if (intScore >= 90)

            strGrade = "You get A.";

        else if (intScore >= 80)

            strGrade = "You get B.";

        else if (intScore >= 70)

            strGrade = "You get C.";

        else if (intScore >= 60)

            strGrade = "You get D.";

        else

            strGrade = "You get F.";

        Console.WriteLine(strGrade);

        if (intScore >= 90 && strMajor == "Information Systems")

            Console.WriteLine("Congratulations! You are one of the best students in IS.");

        else if (intScore >= 90)

            Console.WriteLine("Congratulations! You are one of the best students.");

        else

            Console.WriteLine("");

    }

​

}