#pragma GCC optimize("Ofast,unroll-loops,no-stack-protector")
#pragma GCC target("sse3")
#include "bits/stdc++.h"
using namespace std;
using ll = long long;
using Vi = vector<int>;
using Pii = pair<int,int>;
#define pb push_back
#define mp make_pair
#define x first
#define y second
#define rep(i,b,e) for (int i=(b); i < (e); i++)
#define each(a,x) for(auto& a : (x))
#define all(x) (x).begin(), (x).end()
#define sz(x) int((x).size())

using ull = uint64_t;
ull lim;
int cnt;

int solve(ull mask, int d) {
	if (d <= 0 || (mask&lim) == lim) return 0;
	int best = 5;
	rep(i, 1, cnt) {
		ull alt = mask | (mask<<i);
		if (alt != mask) best = min(best, solve(alt, d-1));
	}
	return best+1;
}

int main() {
	cin.sync_with_stdio(0); cin.tie(0);
	cout << fixed << setprecision(18);

	string s; cin >> s;
	cnt = sz(s);
	lim = (1LL<<cnt) - 1;

	ull mask = 0;
	rep(i, 0, cnt) if (s[i] == '1') mask |= 1LL << i;

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

	cout << solve(mask, 6) << endl;
	return 0;
}