#include <iostream>
#include <string>

int main(int argc,char **argv)
{
    using namespace std;

    string tmp;                                         //LT: Laikinas string skirtas laikyti vartotojo ivesta skaiciu.
                                                        //EN: Temporary string to keep a number from the input.
    if (argc > 1)
    {                                                   //LT: Jei vartotojas ivede skaiciu kaip argumenta komandu eiluteje, ji naudoti.
        tmp = argv[1];                                  //EN: If the user typed the number as an argument in the command line, use it.
    }
    else
    {
        cout << "Prasome ivesti skaiciu: ";             //LT: Jei ne, prasyti vartotojo ivesti skaiciu.
        cin >> tmp;                                     //EN: Otherwise, ast the user for a number.
    }

    int result = 0;                                     //LT: int skirtas laikyti gautai sumai.
                                                        //EN: int to hold the result.
    for(int i = 0; i < tmp.length(); i++)               //LT: Tikrina kiekviena char'a string'e.
    {                                                   //EN: Checks every char in the string.
        if (tmp[i] >= 48 && tmp[i] <= 57)               //LT: Tikrina ar charas yra skaicius.
        {                                               //EN: Checks if the char is a number.
            result += static_cast<int>(tmp[i])-48;      //LT: Jei taip, ji konvertuoja i int. Cia atimama 48, nes char'ai i int'us tieciogiai nesivercia, int'as gaunasi char'o ascii kodas, kodai 48-57 yra 0-9, todel as is kodo atimu 48 kad gaut ivesta skaiciu.
        }                                               //EN: If so, it converts it to an int. Here I subtract 48, because chars don't normally cast to ints, the int ends up being the chars ascii code, codes 48-57 are 0-9, so I subtract 48 to get the inputed number.
    }

    cout << result;                                     //LT: Galiausia, ekrane pasirodo rezultatas!
                                                        //EN: Finally, the result shows up on screen!
    cin.clear();
    cin.ignore(255, '\n');                              //LT: Kad programa neisijungtu vartotojui nespejus perskaityti rezultato, programa palaukia kol vartotojas ka nors paspaus, ir tik tada issijungia.
    cin.get();                                          //EN: The program waits for input before finishing, so the user has time to read the result.
    return 0;
}