#include <bits/stdc++.h>

using namespace std;

typedef long long int ll;
typedef double ld;

typedef pair<ll, ll> ii;
typedef vector<ll> vi;
typedef vector<ii> vii;

#define PB push_back
#define ff first
#define ss second
#define DEB cerr<<"DEB: "

#define FOR(prom,a,b) for(ll prom = (a); prom < (ll)(b); ++prom)
#define ROF(prom,a,b) for(ll prom = (a); prom >= b; --prom)
#define F(a) FOR(i,0,a)
#define FF(a) FOR(j,0,a)

#define EPS (1e-10)
#define EQ(a,b) (fabs(a-b) <= fabs(b-a) * EPS)
#define LINF (1LL<<62LL)

unordered_map<ll, ll> DP;
ll gmini = 99999;
ll success;
string str;

ll solve(ll curr, ll s) {
	if(gmini < s)
		return 99999;
	
	if(curr == success)
		return s;
	
	if(DP.find(curr) != DP.end())
		return DP[curr];
	
	ll mini = 99999;
	F(str.size()-1)
		mini = min(mini, solve(curr | (curr >> (i+1)), s+1));
		
	DP[curr] = mini;
	gmini = min(mini, gmini);
	return mini;
}


int main() {
	cin >> str;
	ll cur = 0;
	if(str[0] == '0') {
		cout << -1 << endl;
		return 0;	
	}

	for(char a : str) {
		cur = cur << 1;
		success = success << 1;
		if(a=='1')
			cur += 1;
		
		success += 1;
	}
	cout << solve(cur, 0) << endl;
	return 0;
}