#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:128000000")
using namespace std;
char s[50];
int f(int l, int r) {
  if (r - l + 1 > 7) return -1;
  if (s[l] == '0' && l != r) return -1;
  int p = 0;
  for (int i = l; i <= r; i++) p = p * 10 + s[i] - '0';
  if (p > 1000000) return -1;
  return p;
}
int main() {
  int k, i, v, u, j, n, m, d, d2, y, r, p, t1, t2, x, l, t, z, fl, to;
  scanf("%s", &s);
  if (strlen(s) < 3) {
    printf("-1\n");
    return 0;
  }
  l = -1;
  n = strlen(s);
  for (i = 1; i <= n - 2; i++)
    for (j = 1; i + j < n; j++) {
      p = 0;
      t = 0;
      p = f(0, i - 1);
      if (p == -1) continue;
      t = p;
      p = f(i, i + j - 1);
      if (p == -1) continue;
      t += p;
      p = f(i + j, n - 1);
      if (p == -1) continue;
      t += p;
      if (t > l) l = t;
    }
  printf("%i\n", l);
  return 0;
}
