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

typedef long long ll;

unordered_set<ll> st;

const int N = 41;
char s[N];

inline bool bit(ll x, int k)
{
	return x & (1LL << k);
}

int main()
{
	scanf("%s", s);
	ll k = 0, m = 1;
	for(char *c = s; *c; c++)
	{
		if(*c == '1') k |= m;
		m <<= 1;
	}
	
	int n = strlen(s);
	m--;
	if(!bit(k, 0))
	{
		puts("-1");
		return 0;
	}
	queue<pair<ll, int>> q;
	q.push({ k, 0 });
	st.insert(k);
	while(!q.empty())
	{
		k = q.front().first;
		int d = q.front().second;
		q.pop();
		if(k == m)
		{
			printf("%d\n", d);
			return 0;
		}
		for(int i = 1; i < n; i++)
		{
			if(!bit(k, i - 1)) break;
			ll x = k | (k << i) & m;
			if(!st.count(x))
			{
				st.insert(x);
				q.push({ x, d + 1 });
			}
		}
	}
}