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

namespace ContestCSharp {
    internal class Program {
        private static void Main() {
            string instr=Console.ReadLine();
            UInt32 answer = 0;
            for (var i = 0; i!= instr.Length; ++i) {
                UInt32 n;
                if (UInt32.TryParse(instr.Substring(i,1),out n )) {
                    answer += n;
                }
            }
            Console.WriteLine(answer);
        }
    }
}