#include <cstdio>
#include <vector>
#include <string>
#include <algorithm>
#include <cstring>

using namespace std;

typedef long long llint;
typedef pair<int, int> pii;

char buff[45];
string tmp;

int main(void) {
  scanf("%s", buff);
  int sol = 1 << 30;
  for (int i = 0; i < (1<<20); ++i) {
    vector<int> V;
    for (int j = 0; j < 20; ++j)
      if (i&(1<<j)) V.push_back(j+1);
    if (V.size() > 6) continue;

    tmp = buff;
    for (auto x: V) {
      auto tmp2 = tmp;
      for (int j = 0; j < tmp.size(); ++j) {
        if (j - x >= 0 && tmp[j-x] == '1') tmp2[j] = '1';
      }
      tmp = tmp2;
    }
    bool ok = 1;
    for (int j = 0; j < tmp.size(); ++j)
      if (tmp[j] == '0') {
        ok = 0; break;
      }
    if (ok) sol = min(sol, (int)V.size());
  }
  if (sol > 50) sol = -1;
  printf("%d\n", sol);
  return 0;
}