#include <bits/stdc++.h>
using namespace std;
char s[35];
int ans = -1, len;
int calc(int l, int r) {
  if (l < r && s[l] == '0') return -1;
  if (r - l + 1 > 7) return -1;
  int cur = 0;
  for (int i = (l); i <= (r); i++) cur = cur * 10 + s[i] - '0';
  if (cur > 1000000) cur = -1;
  return cur;
}
int main() {
  cin.getline(s, 35);
  len = strlen(s);
  for (int i = (1); i <= (min(7, len - 1)); i++)
    for (int j = (i + 1); j <= (len - 1); j++) {
      int a = calc(0, i - 1);
      int b = calc(i, j - 1);
      int c = calc(j, len - 1);
      if (a >= 0 && b >= 0 && c >= 0) ans = max(ans, a + b + c);
    }
  printf("%d\n", ans);
  return 0;
}
