#include <iostream>
#include <string>
#include <bitset>
#include <vector>
#define int long long
using namespace std;

string str;

int res = 6;

bitset<41> mask;

void solve(bitset<41> cur,int k,int x){
	if(x >= str.size())
		return;
	if(cur.count() == str.size()){
		res = min(res,k);
		return;
	}
	if(k >= res)
		return;
		
	auto cur2 = (cur | (cur << (x+1))) & mask;
 
	solve(cur2,k+1,x+1);
	solve(cur,k,x+1);
}



main(){
	ios::sync_with_stdio(false);

	cin >> str;
	bitset<41> bs;
	for(int i=0;i<str.size();i++){
		bs[i] = (str[i] - '0');
		mask[i] = 1;
	}
	//cout<<bs[0]<<endl;
	if(bs[0] == 0){
		cout<<-1<<endl;
		return 0;
	}
	//cout<<"GD"<<endl;
	solve(bs,0,0);
	cout<<res<<endl;
}