/**
*    author:  boutarou
*    created: 02.08.2020 11:53:50
**/

#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>;

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