#include<bits/stdc++.h>
#define endl '\n'
using namespace std;
typedef long long ll;
typedef pair<int, int> PII;
const int N = 1e6+5, M = 1e6+5;
const int MOD = 998244353, INF = 0x3f3f3f3f;
string s;
bool dp[(1 << 16)];
void solve() {
	ll res = 0, t = 1;
	cin >> s;
	for(int i = s.size() - 1; i >= 0; i --) {
		if(s[i] == '1') res += t;
		t <<= 1;
	}
	ll pos = (1 << s.size()) - 1;
	dp[res] = true;
	ll ans = 0, temp = 0;
	while(true) {
		if(dp[pos]) {
			cout << max(0ll, ans - 1)<< endl;
			return ;
		}
		temp <<= 1;
		temp |= 1;
		ans ++;
		vector<bool> t((1 << s.size()), false);
		for(int i = 0; i < (1 << s.size()); i ++) {
			if(dp[i] | dp[(i ^ temp)]) t[i] = true;
		}
		for(int i = 0; i < (1 << s.size()); i ++) dp[i] = t[i];
	}
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr), cout.tie(nullptr);
	int t = 1;
	//cin >> t;
	while(t --) solve();
	
	return 0;
}