#include <bits/stdc++.h>
#define For(i, n) for (int i = 0; i <(n); i++)
#define ForD(i, n) for (int i = (n) - 1; i >= 0; i--)

using namespace std;
typedef long long ll;
typedef unsigned long long ull;

int best = 1<<30;
int n;

void go(ull x, int cnt) {
  if (__builtin_popcountll(x) == n) {
      best = min(best, cnt);
      return;
  }

  if (cnt >= best || cnt > 5) {
    return;
  }

  for (int i = 1; i <= 20; i++) {
    ull y = x | (x >> i);
    go(y, cnt + 1);
  }
}

int main() {
  ios::sync_with_stdio(0);
//0
  string s;
  cin >> s;
  ull x = 0;
  n = s.size();

  For(i, (int)s.size()) {
    x *= 2;
    x += (s[i] - '0');
  }

  if (s[0] != '1') {
    cout << "-1\n";
    return 0;
  }

  go(x, 0);
  if (best >= (1<<30)) {
    cout << "-1\n";
  } else {
    cout << best << "\n";
  }
}