#include <bits/stdc++.h>
using namespace std;
template <typename T, typename TT>
ostream &operator<<(ostream &s, pair<T, TT> t) {
  return s << "(" << t.first << "," << t.second << ")";
}
template <typename T>
ostream &operator<<(ostream &s, vector<T> t) {
  s << "{";
  for (int i = 0; i < t.size(); i++)
    s << t[i] << (i == t.size() - 1 ? "" : ",");
  return s << "}" << endl;
}
int get(string s) {
  if (s.size() == 0) return -10000000;
  if (s.size() > 1 && s[0] == '0') return -10000000;
  if (s.size() > 7) return -10000000;
  stringstream ss;
  ss << s;
  int w;
  ss >> w;
  if (w > 1000000) return -10000000;
  return w;
}
int main() {
  ios_base::sync_with_stdio(0);
  string s;
  cin >> s;
  int best = -1;
  for (int i = 0; i < s.size(); i++)
    for (int j = i; j <= s.size() - 1; j++) {
      string s1 = s.substr(0, i), s2 = s.substr(i, j - i), s3 = s.substr(j);
      (best) = max((best), (get(s1) + get(s2) + get(s3)));
    }
  cout << best;
  return 0;
}
