#include <bits/stdc++.h>
using namespace std;

#define TRACE(x) cerr << #x << ' ' << x << endl
#define FOR(i, a, b) for (int i = (a); i < int(b); i++)
#define REP(i, n) FOR(i, 0, n)
#define _ << ' ' <<

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

#define fi first
#define sec second
#define pb push_back

string s;

void fail() {
  cout << -1;
  exit(0);
}

int n;
int sol = 10;

void check(vector<int> tmp) {
  string s1 = s;

  for(auto k: tmp) {
    string ns = s1;
    REP(i, ns.size()) {
      if(ns[i] == '0' && i - k >= 0 && s1[i - k] == '1') ns[i] = '1';
    }

    s1 = ns;
  }

  REP(i, s1.size()) if(s1[i] == '0') return;

  sol = tmp.size();
}

void rek(int dub, vector<int> tmp, int ls) {
  if(dub >= sol) return;
  check(tmp);

  FOR(i, ls, n + 1) {
    vector<int> ntmp;
    ntmp = tmp;
    ntmp.pb(i);
    rek(dub + 1, ntmp, 2 * i);
  } 
}

int main() {
  
  cin >> s;

  n = s.size();

  vector<int> v;
  rek(0, v, 1);
  
  if (sol == 10) sol = -1;
  cout << sol << endl;
  return 0;
}