/*
   A) Prints the string "true"
   B) Prints the string "false"
   C) Throws NullPointerException
   D) None of the above
*/
public class Regular {
	public static void main(String[] args) {
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < 100; i++) {
			sb.append("a");
		}
		System.out.println((sb + "c").matches("^(a|ab?)*$"));
	}
}