public static void printGrade(double score) {
		if(score < 0 || score > 100) {
			System.out.println("Invalid Score");
			return;
		}
		
		if (score >= 90.0) {
			System.out.println('A');
		} else if(score >= 80.0) {
			System.out.println('B');
		} else if(score >= 70.0) {
			System.out.println('C');
		} else if(score >= 60.0) {
			System.out.println('D');
		} else {
			System.out.println('F');
		}
	}