#include <bits/stdc++.h>
using namespace std;
void subString(string &str, int begin, int end, string &subed) {
  subed = "";
  for (int i = begin; i < end; i++) subed += str[i];
}
int stringToInt(string str) {
  if (str.size() == 1) return str[0] - 48;
  if (str.size() > 1 && str[0] == '0')
    return -1;
  else if (str.size() > 7)
    return -1;
  int val = 0;
  for (int i = 0; i < str.size(); i++) val = val * 10 + (str[i] - 48);
  return val;
}
int main() {
  string mixedScore;
  cin >> mixedScore;
  int highestScore = -1, compareScore = -1;
  int i = 1, j = 2;
  int limitSize = mixedScore.size() - 2;
  int allSize = mixedScore.size();
  string s1, s2, s3;
  int n1, n2, n3;
  while (i <= limitSize) {
    subString(mixedScore, 0, i, s1);
    subString(mixedScore, i, j, s2);
    subString(mixedScore, j, allSize, s3);
    j++;
    if (j == mixedScore.size()) {
      i++;
      j = i + 1;
    }
    n1 = stringToInt(s1);
    n2 = stringToInt(s2);
    n3 = stringToInt(s3);
    if (n1 == -1 || n2 == -1 || n3 == -1)
      continue;
    else if (n1 > 1000000 || n2 > 1000000 || n3 > 1000000)
      continue;
    else
      compareScore = n1 + n2 + n3;
    if (compareScore > highestScore) highestScore = compareScore;
  }
  cout << highestScore << endl;
}
