#include <iostream>
#include <string>

using namespace std;

int main() {
    string in;
    int ans = 0;
    cin >> in;
    for (unsigned int i = 0; i < in.size(); i++) {
        if (('0' <= in[i]) && (in[i] <= '9')) {
            ans += in[i] - '0';
        }
    }
    cout << ans << endl;
    return 0;
}