import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Validate {

	public static void main(String[] args) {

		Scanner input = new Scanner(System.in);
		Boolean isValid = false;

		while( ! isValid ){
			String expression = "(Y|N)";

			Pattern pattern = Pattern.compile(expression, 
				Pattern.CASE_INSENSITIVE);

			System.out.print("Are you sure you want to "+
				"exit the program now? (Y/N)\t:");
			String gender = input.next();

			Matcher matcher = pattern.matcher(gender);
			isValid = matcher.matches();

			if( isValid )
				break;
		}
	}
}