#include <iostream>
using namespace std;
int main() {
    string s; cin >> s;
    int c = 0;
    for (int i = 0; i < s.size(); ++i) {
        if ('1' <= s.at(i) && s.at(i) <= '9') {
            c += s.at(i) - '0';
        }
    }
    cout << c << endl;
}