import java.util.*;

public class Grader {
	public static void main(String [] args) {
		Scanner scanner = new Scanner(System.in);

		int howMany = scanner.nextInt();

		for (int i = 1; i <= howMany; i = i + 1) { 
			System.out.print("Last name: ");
			String lastName = scanner.next();
			System.out.print("First name: ");
			String firstName = scanner.next();
			System.out.print("Midterm: ");
			int midterm = scanner.nextInt();
			System.out.print("Final: ");
			int finalExam = scanner.nextInt();

			processOneStudent(lastName, firstName, midterm, finalExam);
		}
	}

	public static void processOneStudent(String lastName, String firstName, int midterm, int finalExam) {
		double average = calcAverage(midterm, finalExam);
		char grade = calcGrade(average);
		System.out.println("average: " + average + " grade: " + grade);
	}

	public static double calcAverage(int midterm, int finalExam) {
		return (midterm + finalExam) / 2.0;
	}

	public static char calcGrade(double average) {
		char grade;
		if (average >= 90)
			grade = 'A';
		else if (average >= 80)
			grade = 'B';
		else if (average >= 70)
			grade = 'C';
		else if (average >= 60)
			grade = 'D';
		else
			grade = 'F';
		return grade;
	}
}