using System;

public class Program
{
  static void Main()
  {
    string S = Console.ReadLine();
    string S_ = "";
    int _S = 0;
    int result = 0;

    for (int i = 0; i < S.Length; i++)
    {
      S_ = S.Substring(0,1);
      if (int.TryParse(S_, out _S))
      {
        result += _S;
      }
    }

    Console.WriteLine(result.ToString());
  }
}