#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pli = pair<ll, int>;
int Check(string s) {
  if ((s[0] == '0' && int((s).size()) > 1) || int((s).size()) > 7) return -1;
  int num = 0;
  for (char c : s) {
    num *= 10;
    num += (int)(c - '0');
  }
  if (num > 1000000) return -1;
  return num;
}
void Solve() {
  string s;
  cin >> s;
  int n = int((s).size());
  int sum = -1;
  for (int i = 1; i < n - 1; i++) {
    int temp = Check(s.substr(0, i));
    if (temp == -1) continue;
    int best = -1;
    for (int j = i + 1; j < n; j++) {
      int a = Check(s.substr(i, j - i));
      if (a == -1) continue;
      int b = Check(s.substr(j, n - j));
      if (b == -1) continue;
      best = max(best, a + b);
    }
    if (best == -1) continue;
    sum = max(sum, temp + best);
  }
  if (sum < 0) {
    cout << -1;
    return;
  }
  cout << sum;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  Solve();
  return 0;
}
