import javax.swing.JOptionPane;

class MathStudent{
	final double MATH_MIDTERM_PERCENTAGE = .50;
	final double MATH_FINALEXAM_PERCENTAGE = .50;
	
	int midterm = 0;
	int finalExam = 0;
	int research = 0;
	int presentation = 0;
	double finalNumericGrade = 0;
	String finalLetterGrade = "";
	
	public MathStudent()
	{
		System.out.println("MathStudent's constructor");	
	}
	
	public void calculate()
	{
		midterm = Integer.parseInt(JOptionPane.showInputDialog("Enter the midterm grade:"));										
		finalExam = Integer.parseInt(JOptionPane.showInputDialog("Enter the final exam grade:"));
								
		finalNumericGrade = (midterm*MATH_MIDTERM_PERCENTAGE)+(finalExam*MATH_FINALEXAM_PERCENTAGE);
								
		if(finalNumericGrade > 90)
			finalLetterGrade = "A";
		else if((finalNumericGrade >= 83)&(finalNumericGrade < 90))
			finalLetterGrade = "B";
		else if((finalNumericGrade >= 76)&(finalNumericGrade < 83))
		  finalLetterGrade = "C";
		else if((finalNumericGrade >= 65)&(finalNumericGrade < 76))
			finalLetterGrade = "D";
		else 
			finalLetterGrade = "F";	
	}
}