#include <bits/stdc++.h>

using namespace std;

int main() {
    string s;
    cin >> s;

    int ans = 0;
    for (int i = 0; i < s.length(); ++i) {
        if (s[i] >= '1' and s[i] <= '9') {
            ans += s[i] - '0';
        }
    }
    
    cout << ans << endl;
    return 0;
}