using System;

public class Program

{

    public static void Main()

    {

        int count=0, max=0, range=0;

        int []grades = new int[101];

        for(int i=0; i<3; i++)

        {

            Console.WriteLine("What is your grade?");

            int g= int.Parse(Console.ReadLine());

            grades[g]++;

        }

        for(int x=100;x>=0;x--)

        {

            Console.WriteLine(grades[x] + " students got " + x);

        }

        for(int i=0; i<100; i=i+10)

        {

            if(i!=90)

                for(int x=i; x<i+10; x++)

                {

                    count+=grades[x];

                }

            else

                for(int x=i; x<=i+10; x++)

                {

                    count+=grades[x];

                }

            if(count>max)

            {

                max=count;

                range=i;

            }

            count=0;

        }

        if(range!=90)

            Console.WriteLine("The most common grade range was: " + range + "-" + (range+9));

        else

            Console.WriteLine("The most common grade range was: " + range + "-" + (range+10));

​

    } 

}