#include <bits/stdc++.h>

using namespace std;

vector<string> split(const string &str, char delim){
  stringstream ss(str);
  vector<string> res;
  for (string tmp; getline(ss, tmp, delim);) res.push_back(tmp);
  return res;
}

int main() {
  string c1, c2;
  cin >> c1 >> c2;
  auto v = split(c1 + c2, 'x');
  cout << max_element(v.begin(), v.end())->size() << endl;
}