#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef double ld;
typedef pair<ll,ll> ii;
typedef vector<ll> vi;
#define PB push_back()
#define ff first
#define ss second
#define MP make_pair
#define FOR(p,a,b) for(ll p = (a); p < (ll)(b); ++p)
#define F(a) FOR(i, 0, a)
#define FF(a) FOR(j, 0, a)
#define EPS (1e-10)
#define EQ(a,b) (fabs(a-b) <= fabs(a-b)*EPS)
#define DEB(x) cerr << " >>> " << #x << " : " << x << "\n"
string soused(string str, int posun)
{
    string n(str);
    FOR(i,posun,n.size()) if(str[i-posun] == '1') n[i] = '1';
    return n;
}
bool jednicky(string str)
{
    F(str.size())
        if(str[i] == '0') return false;
    return true;
}
int main()
{
    ios::sync_with_stdio(false);
    string str, tmp;
    cin >> str;
    
    if(jednicky(str))
    {
        cout << "0\n";
        return 0;
    }
    if(str[0] == '0')
    {
        cout << "-1\n";
        return 0;
    }
    
    unordered_set<string> veFronte;
    queue<pair<string, int> > fronta;
    
    fronta.push(MP(str,0));
    veFronte.insert(str);
    while(!fronta.empty())
    {
        auto a = fronta.front();
        fronta.pop(); 
        if(a.ss >= 5)
        { 
            cout << "6\n";
            return 0;
        }
        FOR(i,1,21)
        {
            tmp = soused(a.ff, i);
            if(!veFronte.insert(tmp).ss)
                continue;
            if(jednicky(tmp)) 
            {
                cout << a.ss+1 << "\n";
                return 0;
            }
            fronta.push(MP(tmp,a.ss+1));
        }
    }
   
   
    return 0;

}