#include <bits/stdc++.h>
using namespace std;

int main () {

    string S;
    cin >> S;

    int ans = 0;

    for (int i = 0; i < S.size(); i++) {
        if (S[i] >= '1' && S[i] <= '9') {
            ans += (int)(S[i] - '0');
        }
    }

    cout << ans << endl;

    return 0;
}