#include <bits/stdc++.h>

#define rep(i,n) for(int i = 0; i < (n); ++i)

typedef long long ll;

using namespace std;

int best = 6;
string s;
int len;

void bt(int last, int cnt, string &ls) {
	cnt++;
	for (int i = last; i < len; i++) {
		if (cnt >= best) break;
		string tmp = ls;
		
		for(int j= len-i-1; j>=0; j--){
			if(tmp[j] == '1') 
				tmp[j+i]='1';
		}
		bool ok = true;
		for(int j = 0; j < len; j++) {
			if(tmp[j] == '0'){
				ok = false;
				break;
			}
		}
		if(ok)
			best = cnt;
		else
			bt(i, cnt, tmp);
	}
}


int main() {
	cin >> s;
	len = s.length();
	if(s[0] == '0'){
		cout << "-1" << endl;
		return 0;
	}
	bt(1,0,s);
	cout << best << endl;

	return 0;
}