#include <cstdio>
#include <vector>
#include <algorithm>
#include <cmath>
#include <set>
#include <iostream>
#include <cassert>
#include <cstring>
#include <bitset>

#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define REP(i,n) FOR(i,0,n)

#define TRACE(x) cerr << #x << " = " << x << endl
#define _ << " _ " <<

#define pb push_back
#define X first
#define Y second

using namespace std;

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

int n;
string s;

bitset<40> all;

bool check(int depth, int lower, bitset<40> B){
  if (depth == 0){
    return (B & all) == all;
  }

  if (lower >= n) return false;

  if (check(depth-1, lower, B | (B << lower))) return true;
  return check(depth, lower+1, B);
}

int main(){
  ios_base::sync_with_stdio(false);

  bitset<40> B;
  cin >> s;
  n = (int)s.size();

  REP(i,n) if (s[i] == '1') B[i] = 1;
  REP(i,n) all[i] = 1;

  if (B[0] == 0){
    cout << -1 << endl;
    return 0;
  }

  REP(depth,6){
    if (check(depth, 1, B)){
      cout << depth << endl;
      return 0;
    }
  }

  cout << 6 << endl;
  return 0;
}