/**
 * A University conducts a 100 mark exam for its student and grades them as
 * follows. Assigns a grade based on the value of the marks.
 *
 */
import java.util.Scanner;
public class Assignment5 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		System.out.println("Enter mark: ");
		int mark = sc.nextInt();
		if (mark >= 90)
		{
			System.out.println("O Grade");
		}
		else if (mark >= 80)
		{
			System.out.println("O Grade");
		}
		else if (mark >= 70)
		{
			System.out.println("A Grade");
		}
		else if (mark >= 60)
		{
			System.out.println("B Grade");
		}
		else if (mark >= 50)
		{
			System.out.println("C Grade");
		}
		else if (mark >= 40)
		{
			System.out.println("E Grade");
		}
		else
		{
			System.out.println("F Grade");
		}
	}

}