import java.util.Scanner;
class CalculateGrade {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

        System.out.print("Enter the student's score (0-100): ");
        int score = input.nextInt();

        if (score < 0 || score > 100) {
            System.out.println("Invalid score. Please enter a score between 0 and 100.");
        } else {
            char grade;

            if (score >= 90) {
                grade = 'A';
            } else if (score >= 80) {
                grade = 'B';
            } else if (score >= 70) {
                grade = 'C';
            } else if (score >= 60) {
                grade = 'D';
            } else {
                grade = 'F';
            }
            System.out.println("The student's grade is: " + grade);
        }
    }
}