Java Regex: Sum of All Values

/*
 * You are given a keys string and a text string.
 * Write a program that finds the start key and the end key from the keys string and then applies them to the text string.
 * The start key will always stay at the beginning of the keys string.
 * It can contain only letters and underscore and ends just before the first found digit.
 * The end key will always stay at the end of the keys string.
 * It can contain only letters and underscore and starts just after the last found digit.
 * Print at the console the sum of all values (only integer and floating-point numbers with dot as a separator are considered valid)
 *   in the text string, between a start key and an end key. If the value is 0 then print “The total value is: nothing”.
 * If no start key or no end key is found, then print “A key is missing”.
 * The Input will be read from the console.
 * The first line will hold the keys string and the second line will hold the text to search.
 * The output should hold the result text, printed in an HTML paragraph. The actual value of the sum should be italic.
 * The number should been 2 digits rounded after decimal separator.
 */


import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Locale;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class SumOfAllValues {
    public static void main(String[] args) {
        Locale.setDefault(Locale.ROOT);
        String keysStr = "";
        String text = "";

        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

            keysStr = reader.readLine();
            text = reader.readLine();
        } catch (IOException e) {
            e.printStackTrace();
        }

        Pattern keysPattern = Pattern.compile("^([a-zA-Z_]+)\\d.*\\d([a-zA-Z_]+)");
        Matcher keysMatcher = keysPattern.matcher(keysStr);
        if (!keysMatcher.find()) {
            System.out.println("<p>A key is missing</p>");
            return;
        }

        String startKey = keysMatcher.group(1);
        String endKey = keysMatcher.group(2);

        Pattern valuesPattern = Pattern
                .compile(Pattern.quote(startKey) + "([\\d.]+)" + Pattern.quote(endKey));

        Matcher valuesMatcher = valuesPattern.matcher(text);
        double valuesSum = 0;
        while (valuesMatcher.find()) {
            valuesSum += Double.parseDouble(valuesMatcher.group(1));
        }

        if (valuesSum != 0) {
            if (valuesSum == (int) valuesSum) {
                System.out.printf("<p>The total value is: <em>%d</em></p>", (int) valuesSum);
            } else {
                System.out.printf("<p>The total value is: <em>%.2f</em></p>", valuesSum);
            }
        } else {
            System.out.println("<p>The total value is: <em>nothing</em></p>");
        }
    }
}