import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class MainClass {
public static void main(String args[]) {
String regex = "(?=^255).*";
Pattern pattern = Pattern.compile(regex);
String candidate = "255.0.0.1";
Matcher matcher = pattern.matcher(candidate);
if (matcher.find())
ip = matcher.group();
}
}