import java.util.List;

import java.util.Optional;

import java.util.stream.Collectors;

import java.util.stream.IntStream;

import java.util.ArrayList;

import java.util.Arrays;

public class StringCalculator {

public int add(String numbers){

// if(numbers.length()==1) return Integer.parseInt(numbers.substring(0, 1));

// if(numbers.length()>0){

// return add(numbers.substring(0,numbers.length()/2))+add(numbers.substring(numbers.length()/2,numbers.length()));

// }

if(numbers.length()>0){

Optional<String> delimiter = Optional.empty();

if(numbers.startsWith("//")){

String[] splittedNumbers = numbers.split("\n",2);

numbers = splittedNumbers[1];

delimiter = Optional.of(splittedNumbers[0].substring(splittedNumbers[0].length()-1));

}

List<String> nmbs = Arrays.asList(numbers.split(",|\n|"+delimiter.orElse(null)));

List<Integer> negativeNumbers = new ArrayList<>();

List<Integer> parsedNumbers = nmbs.stream().map( number -> {

Integer res = Integer.parseInt(number);

if(res<0){

negativeNumbers.add(res);

return 0;

}

return res;

}).collect(Collectors.toList());

if(! negativeNumbers.isEmpty()) throw new IllegalArgumentException(negativeNumbers.toString());

return parsedNumbers.stream().mapToInt(i-> i.intValue()).sum();

}

return 0;

}

}