import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Main {
public static void main(String[] argv) throws Exception {
}
public static CharSequence removeDuplicateWhitespace(CharSequence inputStr) {
String patternStr = "\\s+";
String replaceStr = " ";
Pattern pattern = Pattern.compile(patternStr);
Matcher matcher = pattern.matcher(inputStr);
return matcher.replaceAll(replaceStr);
}
}