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

#define PII pair<int, int>
#define VI vector<int>
#define VPII vector<PII>
#define LL long long
#define f first
#define s second
#define MP make_pair
#define PB push_back
#define LD long double
#define endl '\n'
#define ALL(c) (c).begin(), (c).end()
#define SIZ(c) (int)(c).size()
#define REP(i, n) for (int i = 0; i < (int)(n); i++)
#define FOR(i, b, e) for (int i = (b); i <= (int)(e); i++)
#define FORD(i, b, e) for (int i = (b); i >= (int)(e); i--)
#define ll LL
#define mp MP
#define pb PB
#define st f
#define nd s
#define eb emplace_back
const int inf = 1e9 + 7;
const LL INF = 1e18L + 7;

#define sim template<class n
sim, class s> ostream & operator << (ostream &p, pair<n, s> x)
{return p << "<" << x.f << ", " << x.s << ">";}
sim> auto operator << (ostream &p, n y) ->
typename enable_if<!is_same<n, string>::value, decltype(y.begin(), p)>::type
{int o = 0; for (auto c : y) {if (o++) p << ", "; p << c;} return p << "}";}
void dor() {cerr << endl;}
sim, class...s> void dor(n p, s...y) {cerr << p << " "; dor(y...);}
sim, class s> void mini(n &p, s y) {if (p > y) p = y;}
sim, class s> void maxi(n &p, s y) {if (p < y) p = y;}

#ifdef DEB
#define debug(...) dor(__FUNCTION__, ":", __LINE__, ": ", __VA_ARGS__)
#else
#define debug(...)
#endif

#define I(x) #x " =", (x), " "
#define A(a, i) #a "[" #i " =", i, "] =", a[i], " "
LL endd;
LL res = 6;
int n;
set<LL> memo;
void back(LL x, int r)
	{
	if(r >= res)return;
	if(x == endd)
		{
		mini(res, r);
		return;
		}
	if(memo.count(x))return;
	memo.insert(x);
	debug(x, r);
	
	vector<LL> V;
	FOR(i, 1, n)
		{
		V.PB(x | (x >> i));
		}
	sort(ALL(V), [](LL x, LL y){return __builtin_popcount(x) > __builtin_popcount(y);});
	
	for(auto i : V)
		back(i, r+1);
	}
int main()
{
	string s;
	cin >> s;
	if(s[0] == '0')
		{
		cout << -1 << endl;
		return 0;
		}
	LL x = 0;
	n = s.size();
	REP(i, s.size())
		{
		x *= 2;
		x += s[i] == '1';
		}
	endd = (1LL << s.size()) - 1;
	back(x, 0);
	cout << res << endl;
}