/*
goat goats
*/
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class MainClass {
public static void main(String[] av) {
String joke = "dog " + "dogs";
String regEx = "dog";
Pattern doggone = Pattern.compile(regEx);
Matcher m = doggone.matcher(joke);
StringBuffer newJoke = new StringBuffer();
while (m.find()) {
m.appendReplacement(newJoke, "goat");
}
m.appendTail(newJoke);
System.out.println(newJoke.toString());
}
}