#include <iostream>
using namespace std;
long long findLastIndex(string& str, char x)
{
long long index = -1;
for (int i = 1; i <=str.length(); i++)
if (str[i] == x)
index = i;
return index;
}
int main()
{
string str;
getline(cin,str);
char x = '0';
long long index = findLastIndex(str, x);
if (index == -1)
cout << "0";
else
cout << index+1;
return 0;
}
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