#include <bits/stdc++.h>
using namespace std;
const double pi = acos(-1.0);
const int INF = (int)1e9;
string s;
int count(int l, int r) {
  int ret = 0;
  if (l < r && s[l] == '0') return -1e8;
  if (r - l + 1 > 7) return -1e8;
  for (; l <= r; l++) {
    ret *= 10;
    ret += s[l] - '0';
  }
  if (ret > 1e6) return -1e8;
  return ret;
}
int main() {
  getline(cin, s);
  int ans = -1;
  if (s.size() < 3) {
    cout << -1;
    return 0;
  }
  for (int i = 0; i < s.size() - 2; i++) {
    for (int j = i + 1; j < s.size() - 1; j++) {
      int a = count(0, i);
      int b = count(i + 1, j);
      int c = count(j + 1, s.size() - 1);
      ans =
          max(ans, count(0, i) + count(i + 1, j) + count(j + 1, s.size() - 1));
    }
  }
  cout << ans;
  return 0;
}
