#include <iostream>
#include <queue>
using namespace std;
using ll = long long;

int sol = 100;
ll bmask = 0, target;

void dfs(ll mask, int step) {
	if (mask == target) {
		sol = min(sol, step);
		return;
	}
	if (step == 6) return;
	for (int i = 1; i <= 20; ++i)
		if ((mask | (mask >> i)) != mask)
			dfs(mask | (mask >> i), step + 1);
}

int main()
{
	string str;
	cin >> str;
	if (str[0] == '0') return cout << -1, 0;
	for (int i = 0; str[i]; ++i)
		bmask = bmask * 2 + str[i] - '0';
	target = (1LL << str.size()) - 1;
	dfs(bmask, 0);
	cout << sol;
	/*
	priority_queue<pair<int, ll> > Q;
	Q.emplace(__builtin_popcount(bmask), bmask);
	while (!Q.empty())
	{
		auto p = Q.top(); Q.pop();
		ll b = p.second;
		if (__builtin_popcount(b) == str.size())
			
	}*/
	
}