public class Main {

public static void main(String[] args) {

int number = 584;

System.out.println("Sum of digits of " + number + " is " + sumDigits(number));

System.out.println(sumDigits(1234));

System.out.println(sumDigits(-125));

System.out.println(sumDigits(4));

System.out.println(sumDigits(32123));

}

public static int sumDigits(int number){

if (number<0){

return -1;

}

if (number<=9){

return number;

}

int sumOfDigits = 0;

while(number!=0){

sumOfDigits += number%10;

number /= 10;

}

return sumOfDigits;

}

}