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

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

int b;
ll goal;

int solve(ll state, int minstep, int used = 0) {
	if (used > 5) return 6;
	if (state == goal) return used;
	int res = 6;
	for (int i=minstep; i < b; i++) {
		res = min(res, solve(state | (state >> i), i, used+1));
	}
	return res;
}

int main () {
	ios::sync_with_stdio(false);
	string in;
	cin >> in;
	if (in[0] == '0') {
		cout << -1 << endl;
		return 0;
	}
	b = in.size();
	goal = (1ll << b) - 1;
	ll start = 0;
	for (int i=0; i<in.size(); i++) {
		start *= 2;
		start += in[i] - '0';
	}
	int res = solve(start, 1);
	cout << res << endl;
}