Softuni Numerals [Exam 28.02.2016]

package com.sve;

        import java.math.BigInteger;
        import java.util.ArrayList;
        import java.util.HashMap;
        import java.util.Map;
        import java.util.Scanner;
        import java.util.regex.Matcher;
        import java.util.regex.Pattern;

public class Main {

    public static void main(String[] args) {
        Map<String, String> values = new HashMap<>();
        values.put("aa", "0");
        values.put("aba", "1");
        values.put("bcc", "2");
        values.put("cc", "3");
        values.put("cdc", "4");
        String regexString = "((aa)|(aba)|(bcc)|(cc)|(cdc))";
        Pattern regexPattern = Pattern.compile(regexString);
        Scanner scan = new Scanner(System.in);
        String inputLine = scan.nextLine();
        Matcher matcher = regexPattern.matcher(inputLine);
        StringBuilder result = new StringBuilder();
        while (matcher.find()) {
            result.append(values.get(matcher.group(1)));
        }
        BigInteger resultInteger = new BigInteger(result.toString(), 5);
        System.out.println(resultInteger);
    }
}