#include <iostream>
#include <string>

using namespace std;

static void setup()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
}

static void run()
{
    string s;
    cin >> s;

    auto sum = 0;
    for (const auto c : s) {
        if (c >= '0' && c <= '9') {
            sum += c - '0';
        }
    }
    cout << sum << endl;
}

int main(int argc, char **argv)
{
    setup();
    run();
    return 0;
}