Girilen notun harf notu olarak yazılması

package not_cevirisi;

import javax.swing.JOptionPane;


public class Not_cevirisi {

    
    public static **** main(String[] args) {
       Integer not=Integer.parseInt
               (JOptionPane.showInputDialog("Notunuzu giriniz"));
       
         String harf=" ";
         
         if (not>=90)
         {
           harf="A1";
        JOptionPane.showMessageDialog(null,"Notunuz: "+not+" "+ harf);
         
         }
        
       
        else if (not>=80)
        {
           harf="A2";
        JOptionPane.showMessageDialog(null,"Notunuz: "+not+" "+harf);
        
        }
         
        else if (not>=70)
        {
          harf="B1";
         JOptionPane.showMessageDialog(null,"Notunuz: "+not+" "+ harf);
        }
       
        else if (not>=65)
        {
            harf="B2"; 
          JOptionPane.showMessageDialog(null,"Notunuz: "+not+" "+ harf);
        }
    
        else if (not>=60)
        {
            harf="C";
         JOptionPane.showMessageDialog(null,"Notunuz: "+not+" "+ harf);
        }
         
        else if (not<60)
                {
                harf="D";
                JOptionPane.showMessageDialog(null,"Notunuz: "+not+" "+ harf);
                
                }
}

}