using System;
using System.Linq;

class Program
{
    static void Main(string[] args)
    {
        string S = Console.ReadLine();
        int ans = 0;

        for (int i = 0; i < S.Length; i++)
        {
            if (S[i] < 48 || 57 < S[i]) continue;

            ans += int.Parse(S[i].ToString());
        }
        Console.WriteLine(ans);
    }
}