import java.util.*;

public class NumericToLetterGrade {
  public static void main(String[] args) {
    int x;
    char c='O';
    System.out.println("Enter numeric grade: ");
    Scanner keyboard = new Scanner(System.in);
    x = keyboard.nextInt();
    if(x<=100 && x >= 90){
      c = 'A';
    }
    if(x<90 && x >= 80){
      c = 'B';
    }
    if(x<80 && x >= 70){
      c = 'C';
    }
    if(x<70 && x >= 60){
      c = 'D';
    }
    if(x<60){
      c = 'F';
    }
    System.out.println("Your letter grade is: "+c);
  }
}