#include <iostream>
#include <string>

using namespace std;

int main() {
    string s; 
    int length, sum = 0;
    cin >> s;

    length = s.size();

    for (int i = 0; i < length; i++) { 
        if (s[i] >= '0' && s[i] <= '9') {
            sum += s[i] - '0';
        }
    }
    cout << sum << endl;

    return 0;
}