using System;

public class Program

{

    public static void Main()

    {

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

        {

        Console.WriteLine("Enter the mark:");

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

         string b = a>=90 && 100>=a? " S grade" : a>=80 && 90>a? "A Grade" : a>=70 && 80>=a? "B Grade" :a>=60 && 70>a? "C Grade" :a>=50 && 60>a? "D Grade" : a>=40 && 50>a? "E Grade" :"Invalid Marks";

        Console.WriteLine(b);

        }

    }

}