How to Make a Grade Maker in Java

import java.util.Scanner;
 
public class Grader{
    public static void main(String[] args){
        Grader instance = new Grader();
        System.out.print("Enter your grade: ");
        Scanner input = new Scanner(System.in);
 
        try{
            int grade = Integer.parseInt(input.nextLine());
            instance.gradeMarks(grade);
        }catch(Exception e){
            System.err.println("This is not a number.");
        }
    }
 
    public void gradeMarks(int grade){
        String mark = "F";
 
        if(grade >= 90 && grade <= 100){
            mark = "A";
        }else if(grade >= 80 && grade <= 89){
            mark = "B";
        }else if(grade >= 70 && grade <= 79){
            mark = "C";
        }else if(grade >= 60 && grade <= 69){
            mark = "D";
        }
 
        System.out.printf("Your mark is %s.\n", mark);
    }
}