/**
 *
 *  IF ELSE IF Ladder
 * */
public class Main {

	public static void main(String[] args) {

		int marks = 70;

		if (marks < 50) {
			System.out.println("fail");
		} else if (marks >= 30 && marks < 60) {
			System.out.println("D grade");
		} else if(marks >= 60 && marks < 70){
			System.out.println("C grade");
		} else if(marks >= 70 && marks < 80){
			System.out.println("B grade");
		} else if (marks >= 80 && marks < 90){
			System.out.println("A grade");
		} else if (marks >= 90 && marks < 100){
			System.out.println("A+ grade");
		} else {
			System.out.println("Invalid Marks");
		}
	}
}