#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for (int (i)=(0);(i)<(int)(n);++(i))
using ll = long long;
using P = pair<int, int>;
using namespace std;

int main() {
    string s;
    cin >> s;
    int ans = 0;
    rep(i, s.size()) {
        if ('0' <= s[i] and s[i] <= '9') {
            ans += s[i]-'0';
        }
    }

    cout << ans << endl;
    return 0;
}