#include<bits/stdc++.h>
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) (int) (x).size()
#define pb push_back
#define fi first
#define se second

using namespace std;

typedef long long LL;
typedef vector<int> VI;
typedef pair<int, int> PII;
typedef long double LD;

int n, found = 6;
LL ALL;

int foo(LL mas, int ile = 0) {
	if(mas == ALL) return ile;
	if(ile >= found-1) return found;
	int res = 32;
	for(int i=1; i<n; i++) {
		res = min(res, foo(mas | ((mas << i) & ALL), ile+1));
	}
	return res;
}

int main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	string x;
	cin >> x;
	n = (int)x.size();
	LL mas = 0;
	for(int i=0; i<n; i++) if(x[i] == '1') mas |= (1LL<<i);
	ALL = (1LL<<n) - 1;
	if(x[0] == '0') cout << -1 << "\n";
	else cout << foo(mas) << "\n";
}