#include <bits/stdc++.h>
using namespace std;
string s;
int num, ans;
int main()
{
	cin >> s;
	s = s + '1';
	for (int i = 0;i < s.size();i++)
	{
		if (s[i] == '0')
		{
			num++;
		}
		else
		{
			ans = max (ans, num);
			num = 0;
		}
	}
	cout << ans;
	return 0;
}