#include <algorithm>
#include <array>
#include <cstdio>
#include <iostream>
#include <numeric>
#include <optional>
#include <vector>

using namespace std;

int main() {
    string s;
    cin >> s;
    int32_t sum = 0;
    for (auto c : s) {
        if ('0' <= c && c <= '9') {
            sum += c - '0';
        }
    }
    cout << sum << endl;
    return 0;
}