#include <iostream>
using namespace std;

int main() {
    string S;
    cin >> S;
    int total = 0;
    for (int i = 0; i < S.length(); i++) {
        char x = S.at(i);
        if (x >= 48 && x <= 57) {
            total += x - 48;
        }
    }
    cout << total << endl;

    return 0;
}