import java.util.regex.*;

public class catastrophic {

    public static void main(String[] args) {

        for (int runs = 0; runs < 2; runs++) {

            //Pattern pattern = Pattern.compile("(0*)*A");

            //Pattern pattern = Pattern.compile("a?{20}a{20}");

            // Run from 5 to 25 characters

            for (int length = 5; length < 30; length++) {

                Pattern pattern = Pattern.compile("(a*)*b");

                // Build input of specified length

                String input = "";

                for (int i = 0; i < length; i++) { input += "a"; }

                // Measure the average duration of two calls...  

                long start = System.nanoTime();

                for (int i = 0; i < 2; i++) {

                    pattern.matcher(input).find();

                }

                System.out.println(length + " " + input + ": " 

                       + ((System.nanoTime() - start) / 2000000000d) 

                       + "s");

            }

        }

    }

}