#include <iostream>
#include <cmath>
#define lli long long int
using namespace std;

lli resN, maxLevel;
int len;
long long int shif(long long int num, long long int k) {
	long long int s = num >> k;
	return s | num;
}

void rec(lli level, lli num) {
	if (level > maxLevel) {
		return;
	}
	if (num == resN) {
		if (level < maxLevel) { 
			maxLevel = level;
		}
		return;
	}
	for (int i = 1; i < len; ++i) {
		 //cout << i << " " << num << endl;
		rec(level+1, shif(num, i));
		
	}
}

int main() {
	string k;
	cin >> k;
	if (k[0] == '0') {
		cout << "-1" << endl;
		return 0;
	}
	lli num = 0;
	len = k.length();
	for (int i = 0; i < len; ++i) {
		if (k[i] == '1') {
			num += pow(2, len - 1 - i);
		} 
	}
	//cout << num << endl;
	maxLevel = 100000;
	resN = pow(2, len) - 1;
	if ( num == resN) { cout << 0 << endl; return 0; }
	rec(1, num);
	cout << maxLevel - 1<< endl;
	return 0;
}