using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Enter the percentage");

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

        if(percentage>=85)

        {Console.WriteLine("grade:A");

    }   else if(percentage>=75 && percentage<85)

        {Console.WriteLine("grade:B");

        }else if(percentage>=65 && percentage<75)

        {Console.WriteLine("grade:C");

        }else if(percentage<65)

            Console.WriteLine("grade:D");

        Console.ReadLine();

    }

}