#include <iostream>
#include <string>
#include <stdlib.h>

class sumNumber
{
private:
    int m_sum;
    std::string m_iData;

public:
    sumNumber() : m_sum(0), m_iData("") {};

    void read();
    void sum();
    void show();
};

void sumNumber::read()
{
    std::cin >> m_iData;
}

void sumNumber::sum()
{
    for (int i = 0; i < m_iData.size(); ++i) {
        int tNum = m_iData[i] - 0x30;
        if (0 > tNum && 9 < tNum) {
            continue;
        }
        m_sum += tNum;
    }
}

void sumNumber::show()
{
    std::cout << m_sum << std::endl;
}

int main()
{
    sumNumber obj;

    obj.read();
    obj.sum();
    obj.show();
}