import java.util.Scanner;
public class PrintGader {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.print("Your score is：");
        int sc = input.nextInt();
        printGrader(sc);//调用方法
     }
    public static void printGrader(int score){
        if (score<0 || score>100){
            System.out.println("The score is invalid.");
        }
        else if(score < 40){
            System.out.println("The corresponding is F.");
        }
        else if(score < 70){
            System.out.println("The corresponding is B.");
        } 
        else {
            System.out.println("The corresponding is E.");
        }
    }
    
}