using System;
using System.Linq;
using System.Collections.Generic;

namespace Kumite
{
  public class Problem
  {
    public static int SumDigitsOf(long integer)
    {
      return integer.GetDigits().Sum();
    }
  }
  
  public static class LongExtensions
  {
    public static IEnumerable<int> GetDigits(this long number)
    {
      number = Math.Abs(number);
      
      while (number > 9)
      {
        yield return (int)(number % 10);
        number /= 10;
      }
      
      yield return (int)number;
    }
  }
    
}