#include <bits/stdc++.h>
using namespace std;
int main(int argc, char **argv) {
  string d;
  cin >> d;
  if ((d.length() < 3) || (d.length() > 21)) {
    cout << -1 << endl;
    return 0;
  }
  int max = -1;
  for (int i = 1; i < d.length() - 1; ++i) {
    for (int j = i + 1; j < d.length(); ++j) {
      string a = d.substr(0, i);
      string b = d.substr(i, j - i);
      string c = d.substr(j, d.length() - j);
      if ((a.length() > 1) && (a[0] == '0') || (a.length() > 7)) continue;
      if ((b.length() > 1) && (b[0] == '0') || (b.length() > 7)) continue;
      if ((c.length() > 1) && (c[0] == '0') || (c.length() > 7)) continue;
      int na = atoi(a.c_str());
      int nb = atoi(b.c_str());
      int nc = atoi(c.c_str());
      if ((na > 1000000) || (nb > 1000000) || (nc > 1000000)) continue;
      int sum = na + nb + nc;
      if (sum > max) max = sum;
    }
  }
  cout << max << endl;
  return 0;
}
