#include <iostream>
#include <string>
using namespace std;

int main() {
    string s; cin >> s;
    int r = 0;
    for (int i = 0; i < s.length(); ++i) {
        if (isdigit(s.at(i))) r += (int)(s.at(i) - '0');
    }
    cout << r << endl;
}