[백준] 자바: 9498번

import java.util.Scanner;

public class Main{
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        
        int score = in.nextInt();
        
        if(90 <= score)
            System.out.println('A');
        else if(80 <= score)
            System.out.println('B');
        else if(70 <= score)
            System.out.println('C');
        else if(60 <= score)
            System.out.println('D');
        else
            System.out.println('F');
    }
}