#include <bits/stdc++.h>
using namespace std;
int f(string s) {
  int sum = 0;
  for (int i = 0; i < s.size(); i++) {
    sum = sum * 10 + (s[i] - '0');
  }
  return sum;
}
int main() {
  string s, a, b, c;
  cin >> s;
  int n, m, ans = 0, maxn;
  a = "";
  maxn = -1;
  for (int i = 0; i < s.size(); i++) {
    ans = 0;
    a += s[i];
    b = "";
    for (int j = i + 1; j < s.size(); j++) {
      b += s[j];
      c = "";
      for (int k = j + 1; k < s.size(); k++) {
        c += s[k];
      }
      if (c.size() == 0) continue;
      if ((a[0] == '0' && a.size() >= 2) ||
          (a.size() > 7 || (a.size() == 7 && a != "1000000")))
        continue;
      if ((b[0] == '0' && b.size() >= 2) ||
          (b.size() > 7 || (b.size() == 7 && b != "1000000")))
        continue;
      if ((c[0] == '0' && c.size() >= 2) ||
          (c.size() > 7 || (c.size() == 7 && c != "1000000")))
        continue;
      ans = f(a) + f(b) + f(c);
      maxn = max(ans, maxn);
    }
  }
  printf("%d\n", maxn);
}
