using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Minimalna_liczba
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Podaj N");
            int A = Convert.ToInt32(Console.ReadLine());
            char[] chars;
            for (; ;)
            {
                string input = Console.ReadLine();
                if (input.Length==A)
                {
                    chars = input.ToCharArray();
                    break;
                }
            }
            int i = 0, sum=0, prog=0;
            string number = "";
            for(; ;)
            {
                int q;
                if(Int32.TryParse(chars[i].ToString(),out q)&&prog==0)
                {
                    number += chars[i];
                    prog = 1;
                    if(i==chars.Length-1)
                    {
                        sum += Convert.ToInt32(number);
                    }
                }
                else if(prog==1)
                {
                    if (Int32.TryParse(chars[i].ToString(), out q))
                    {
                        number += chars[i];
                    }
                    else
                    {
                        sum += Convert.ToInt32(number);
                        prog = 0;
                        number = "";
                    }
                }
                i++;
                if (i==chars.Length)
                {
                    break;
                }
            }
            Console.WriteLine(sum);
            Console.Read();

        }
    }
}