채우다

https://www.acmicpc.net/problem/9498

import java.util.*;

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