#include <bits/stdc++.h>
using ll = long long;
using llu = long long unsigned;

using namespace std;

int main() {
    string S;
    cin >> S;
    int result = 0;
    for (auto c : S) {
        if ('1'<=c && c<='9') { result += (c-'0'); }
    }
    cout << result << endl; return 0;
}