#include "bits/stdc++.h"
using namespace std;
using ll = long long;
using ld = long double;
using P = pair<int, int>;
using vi = vector<int>;
using vvi = vector<vi>;
const int INF = 1e9;
#define rep(i, n) for(int i = 0; i < (n); i++)
#define rep2(i, x, n) for(int i = x; i < (n); i++)
#define all(n) begin(n), end(n)
const long long llINF = 1LL << 60;

void Main() {
    string s;
    cin >> s;
    int ans = 0;
    rep(i, s.size()) {
        if('0' <= s[i] && s[i] <= '9') {
            ans += (s[i] - '0');
        }
    }
    cout << ans << endl;
}

int main() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << std::fixed << std::setprecision(15);
    Main();
    return 0;
}